Researcher basic information

• Studies on the steroidogenic enzyme system for ovarian estrogen biosynthesisi of Japanese eel, Anguilla japonica, Hokkaido University

• https://researchmap.jp/read0118772?lang=en

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=200901088102943913

• 200901088102943913

• oocyte maturation
• sturgeon
• tilapia
• eel
• fish reproduction
• fish steroidogenesis
• sex differentiation in fish
• reproductive physiology in fish
• Reproductive fish physiology

• Life Science, Aquatic bioproduction science

• Bachelor's degree program, School of Fisheries Sciences
• Master's degree program, Graduate School of Environmental Science
• Doctoral (PhD) degree program, Graduate School of Environmental Science

Research activity information

• Mar. 2025, 日本水産学会, 令和6年度水産学進歩賞
  魚類の卵巣の分化から卵成熟までを制御するステロイドホルモン産生機構の解明
  井尻成保

• Sexual dimorphic expression pattern of sex differentiation–related genes and the W–chromosome–specific gene during gonadal sex differentiation in Kaluga sturgeon (Huso dauricus)
  Kazuki Tousaka; Ryohei Surugaya; Shun Yoshida; Shinji Adachi; Shigeho Ijiri
  Aquaculture, 622, 744027, 744027, Elsevier BV, Jul. 2026, [Peer-reviewed], [Last author, Corresponding author]
  English, Scientific journal
• Faecal inorganic matter affects androgen metabolite levels in seals before migration
  Mayuko Otsuki; Takanori Horimoto; Motoki Kobayashi; Shigeho Ijiri; Yoko Mitani
  Journal of Experimental Marine Biology and Ecology, 597, 152178, 152178, Elsevier BV, Apr. 2026
  Scientific journal
• Role of gonadal soma-derived growth factor (gsdf) on sex-differentiation in Nile tilapia, Oreochromis niloticus
  Tomomitsu Arai; Sakura Tanaka; Megumi Sakon; He Gao; Shigeho Ijiri
  General and Comparative Endocrinology, 377, 114884, 114884, Elsevier BV, Feb. 2026, [Peer-reviewed], [Last author, Corresponding author]
  English, Scientific journal
• Heterogeneous but not homogeneous knockout of follicle-stimulating hormone receptor (fshr) leads to sexual reversal in genetic XX female Nile tilapia
  He Gao; Tomomitsu Arai; Hongwei Yan; Keita Furukawa; Takeshi Kitano; Shigeho Ijiri
  Aquaculture, 613, 743360, 743360, Elsevier BV, Feb. 2026, [Peer-reviewed], [Last author, Corresponding author]
  English, Scientific journal
• Generation of WW Superfemale Sturgeons Through Hormonal Masculinization of ZW Females
  Ryohei Surugaya; Kazuki Tousaka; Shun Yoshida; Shinji Adachi; Shigeho Ijiri
  Fishes, 10, 12, 618, 618, MDPI AG, 02 Dec. 2025, [Peer-reviewed], [Last author, Corresponding author]
  English, Scientific journal, In sturgeon aquaculture, all-female production is desirable due to the high value of caviar. Genetic sexing and the production of WW superfemales are important steps toward achieving this. In this study, we identified the WSR and ZSR primers for amplification of W- and Z-specific regions, respectively. WSR primers were designed on the gene W-linked RT RNase H-like domain containing protein (rnhW). The polymerase chain reaction (PCR) bands were obtained with the WSR primer only in phenotypic female sturgeons, indicating that stable genetic sexing was achieved in most species, including those captured around Hokkaido. Moreover, rnhW showed female-specific expression in the gonads during early sex differentiation in kaluga and Amur sturgeon. ZSR primers were developed from the orofacial cleft 1 candidate gene 1 protein homolog. Clear and distinct gel band patterns for ZZ, ZW, and WW genotypes were obtained using WSR and ZSR primers, consistent with genotypic estimations by quantitative PCR. This consistency confirmed the presence of WW superfemales among offspring produced by fertilizing ZW females with ZW pseudomales masculinized using 17α-methyltestosterone. Our findings provide new insights into the mechanisms of sex determination and differentiation in sturgeons, bringing the establishment of an all-female production system within reach.
• The Involvement of Follicle-Stimulating Hormone in Testis Differentiation in Nile Tilapia
  He Gao; Tomomitsu Arai; Chak Aranyakanont; Dan Li; Megumi Tada; Shigeho Ijiri
  Fishes, 10, 10, 473, 473, MDPI AG, 23 Sep. 2025, [Peer-reviewed], [Invited], [Last author, Corresponding author]
  English, Scientific journal, In Nile tilapia, one of the most important aquaculture species, males are larger than females, and an all-male monosex culture offers significant economic benefits. Although the pituitaries of genetic female (XX) and genetic male (XY) tilapia have identical expression levels of follicle-stimulating hormone (fsh), FSH receptor (fshr) expression remains relatively low in XY-undifferentiated gonads and then increases following morphological sex differentiation. The expression patterns of genes related to androgen biosynthesis in XY-undifferentiated gonads are similar to those of fshr during testis differentiation. This might imply that FSH has a potential function in testis differentiation through regulating the expression of genes related to androgen biosynthesis. To determine whether FSH signaling regulated androgen biosynthesis, we microinjected recombinant FSH (rFsh) into XY larvae during the early sex-differentiation stage. We compared the expression of various genes related to testis differentiation after injection. The genes hsd3b, cyp17a1, dmrt1, and gsdf were found to have higher expression in the rFsh treatment group. These results suggest that FSH signaling can activate androgen biosynthesis by regulating steroidogenic enzymes, including hsd3b and cyp17a1. Moreover, injected rFsh can upregulate dmrt1, which has a positive effect on the expression of gsdf. Therefore, during testis differentiation and development, FSH plays a role in both androgen synthesis and the expression of genes related to testis differentiation in Nile tilapia.
• The Potential Role of Gonadotropic Hormones and Their Receptors in Sex Differentiation of Nile Tilapia, Oreochromis niloticus
  He Gao; Hongwei Yan; Tomomitsu Arai; Chak Aranyakanont; Shuang Li; Shigeho Ijiri
  International Journal of Molecular Sciences, 26, 11, 5376-1, 5376-18, MDPI AG, 04 Jun. 2025, [Peer-reviewed], [Invited], [Last author, Corresponding author]
  English, Scientific journal, Nile tilapia, as an ideal model for studying sex differentiation, is a popular farmed fish worldwide with a stable XX/XY sex-determination system. In tilapia, ovarian differentiation is triggered by estradiol-17β (E2) production in undifferentiated gonads. In a previous study, we suggested that follicle-stimulating hormone (FSH) signaling might be involved in ovarian differentiation in Nile tilapia. In this study, we further investigated the role of FSH signaling in ovarian differentiation via aromatase expression, which converts testosterone to E2. Masculinization of XX fry by aromatase inhibitor or 17α-methyltestosterone leads to suppression of fshr expression. Feminization of XY fry by E2 treatment increased fshr expression from 15 days after hatching, when E2 treatment was terminated. XX tilapia developed ovaries harboring aromatase expression if fsh and fshr were double knockdowns by morpholino-oligo injections. Finally, the transcriptional activity in the upstream region of the aromatase gene (cyp19a1a) was further increased by FSH stimulation when HEK293T cells were co-transfected with foxl2 and ad4bp/sf1. Collectively, this study suggests that the role of FSH signaling is not critical in tilapia ovarian differentiation; however, FSH signaling may have a compensatory role in ovarian differentiation by increasing cyp19a1a transcription in cooperation with foxl2 and ad4bp/sf1 in Nile tilapia.
• Identification and expression of nuclear receptor genes during nutritive phagocyte development in sea urchin Mesocentrotus nudus gonads
  Kazuhiro Ura; Shiori Tsue; Takushi Sato; Seishi Hagihara; Mizuha Satoh; Ichiro Higuchi; Heng Wang; Osamu Nishimiya; Shigeho Ijiri; Yasuaki Takagi
  General and Comparative Endocrinology, 366, 114715, 114715, Elsevier BV, Apr. 2025, [Peer-reviewed]
  English, Scientific journal
• The size of the sperm head influences the gynogenetic success in teleost fish
  Moe Takeuchi; Yoshifumi Kawamura; Tomomitsu Arai; Shigeho Ijiri; Eisuke Takahashi; Etsuro Yamaha; Takafumi Fujimoto; Toshiya Nishimura
  Aquaculture, 596, 741768, 741768, Elsevier BV, Feb. 2025, [Peer-reviewed]
  English, Scientific journal
• The effects of parasitism on sex allocation of a hermaphroditic acorn barnacle
  Masami M Tamechika; Hiroyuki Yamada; Shigeho Ijiri; Yoichi Yusa
  Journal of Evolutionary Biology, 38, 3, 417, 429, Oxford University Press (OUP), 28 Jan. 2025, [Peer-reviewed]
  English, Scientific journal, Abstract
  
  Sex allocation theory predicts the adaptive allocation of resources to male versus female reproduction in simultaneous hermaphrodites in response to individual characteristics or environmental factors. Because parasites uptake resources from their hosts, their presence could affect the sex allocation of the hosts. We investigated the effects of infestation status and infestation intensity by the rhizocephalan barnacle Boschmaella japonica on reproduction, including sex allocation, of the host intertidal barnacle Chthamalus challengeri. Feeding activity was also examined as a factor related to resource intake. Both male and female reproductive investment decreased with increasing parasite infestation, and the sex allocation of large-infested hosts was more male-biased than that of large uninfested hosts. Moreover, in contrast to the model prediction that male investment does not change under resource limitation, male investment decreased in infested hosts whose resources were taken by parasites. This reduction in male investment could be explained by changes in mating group size, since infested hosts have shorter penises and consequently are able to access fewer mating partners.
• Role of follicle-stimulating hormone in gonadal sex differentiation via expression of steroidogenic enzymes in Nile tilapia, Oreochromis niloticus
  He Gao; Tomomitsu Arai; Chak Aranyakanont; Dan Li; Megumi Tada; Shigeho Ijiri
  Fisheries Science, 91, 1, 13, 23, Springer Science and Business Media LLC, 05 Nov. 2024, [Peer-reviewed], [Last author, Corresponding author]
  English, Scientific journal
• Identification of maturation-inducing steroid in sturgeons via comprehensive analyses of steroids produced during oocyte maturation.
  Yuya Hasegawa; Ryohei Surugaya; Kazuki Tousaka; Shinji Adachi; Shigeho Ijiri
  The Journal of steroid biochemistry and molecular biology, 238, 106442, 106442, Apr. 2024, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
  English, Scientific journal, Although 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) and 17α, 20β, 21-trihydroxy-4-pregnen-3-one (20β-S) have been identified as maturation-inducing steroids (MIS) in several teleosts, to date, no MISs have been identified in sturgeons. As it remains possible that an unidentified steroid is an MIS in sturgeons, this study aimed to identify a sturgeon MIS via comprehensive analyses and maturation-inducing (MI) assay of C21 steroids. In vivo and in vitro comprehensive analyses of C21 steroids revealed that serum DHP concentrations were rapidly elevated in the oocyte maturation phase and the DHP production level was notably high among C21 steroids. MI assay indicated that the MI activity of DHP, 17α-hydroxyprogesterone (17OHP), a precursor of DHP, 17α, 20α-dihydroxy-4-pregnen-3-one (αDHP), and 20β-S was high among C21 steroids, but the MI activity of these steroids were similar. In the C21 steroids produced in ovarian follicles during oocyte maturation, 17OHP, αDHP, and unidentified compounds had a low production level, and 20β-S was suggested to be metabolized from DHP after oocyte maturation. Against this background, this study concluded that DHP is a steroid that possesses strong MI activity and is highly produced during oocyte maturation. Although this study could not identify an MIS in sturgeons by fractionation of plasma and subsequent bio assay, it was suggested that DHP is a major MIS in sturgeons.
• mRNA expression profiles of proteolytic genes during the process of ovulation in ovarian follicles of sturgeons
  Ryohei Surugaya; Yuya Hasegawa; Kazuki Tousaka; Shinji Adachi; Shigeho Ijiri
  Fisheries Science, 90, 1, 41, 51, Jan. 2024, [Peer-reviewed], [Last author, Corresponding author]
  English, Scientific journal
• Variation in responses to photoperiods and temperatures in Japanese medaka from different latitudes.
  Ai Shinomiya; Daisuke Adachi; Tsuyoshi Shimmura; Miki Tanikawa; Naoshi Hiramatsu; Shigeho Ijiri; Kiyoshi Naruse; Mitsuru Sakaizumi; Takashi Yoshimura
  Zoological letters, 9, 1, 16, 16, 22 Jul. 2023, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Seasonal changes are more robust and dynamic at higher latitudes than at lower latitudes, and animals sense seasonal changes in the environment and alter their physiology and behavior to better adapt to harsh winter conditions. However, the genetic basis for sensing seasonal changes, including the photoperiod and temperature, remains unclear. Medaka (Oryzias latipes species complex), widely distributed from subtropical to cool-temperate regions throughout the Japanese archipelago, provides an excellent model to tackle this subject. In this study, we examined the critical photoperiods and critical temperatures required for seasonal gonadal development in female medaka from local populations at various latitudes. Intraspecific differences in critical photoperiods and temperatures were detected, demonstrating that these differences were genetically controlled. Most medaka populations could perceive the difference between photoperiods for at least 1 h. Populations in the Northern Japanese group required 14 h of light in a 24 h photoperiod to develop their ovaries, whereas ovaries from the Southern Japanese group developed under 13 h of light. Additionally, Miyazaki and Ginoza populations from lower latitudes were able to spawn under short-day conditions of 11 and 10 h of light, respectively. Investigation of the critical temperature demonstrated that the Higashidori population, the population from the northernmost region of medaka habitats, had a critical temperature of over 18 °C, which was the highest critical temperature among the populations examined. The Miyazaki and the Ginoza populations, in contrast, were found to have critical temperatures under 14 °C. When we conducted a transplant experiment in a high-latitudinal environment using medaka populations with different seasonal responses, the population from higher latitudes, which had a longer critical photoperiod and a higher critical temperature, showed a slower reproductive onset but quickly reached a peak of ovarian size. The current findings show that low latitudinal populations are less responsive to photoperiodic and temperature changes, implying that variations in this responsiveness can alter seasonal timing of reproduction and change fitness to natural environments with varying harshnesses of seasonal changes. Local medaka populations will contribute to elucidating the genetic basis of seasonal time perception and adaptation to environmental changes.
• Soy Isoflavones Induce Feminization of Japanese Eel (Anguilla japonica)
  Hiroyuki Inaba; Yuzo Iwata; Takashi Suzuki; Moemi Horiuchi; Ryohei Surugaya; Shigeho Ijiri; Ai Uchiyama; Ryoko Takano; Seiji Hara; Takashi Yazawa; Takeshi Kitano
  International Journal of Molecular Sciences, 24, 1, 396, 396, MDPI AG, 26 Dec. 2022, [Peer-reviewed]
  English, Scientific journal, Under aquaculture conditions, Japanese eels (Anguilla japonica) produce a high percentage of males. However, females gain higher body weight and have better commercial value than males, and, therefore, a high female ratio is required in eel aquaculture. In this study, we examined the effects of isoflavones, genistein, and daidzein on sex differentiation and sex-specific genes of eels. To investigate the effects of these phytoestrogens on the gonadal sex, we explored the feminizing effects of soy isoflavones, genistein, and daidzein in a dose-dependent manner. The results showed that genistein induced feminization more efficiently than daidzein. To identify the molecular mechanisms of sex-specific genes, we performed a comprehensive expression analysis by quantitative real-time PCR and RNA sequencing. Phenotypic males and females were produced by feeding elvers a normal diet or an estradiol-17β- or genistein-treated diet for 45 days. The results showed that female-specific genes were up-regulated and male-specific genes were down-regulated in the gonads, suggesting that genistein induces feminization by altering the molecular pathways responsible for eel sex differentiation.
• In vitro and in vivo gene transfer in the cloudy catshark Scyliorhinus torazame.
  Chika Fujimori; Chie Umatani; Misaki Chimura; Shigeho Ijiri; Hisanori Bando; Susumu Hyodo; Shinji Kanda
  Development, growth & differentiation, 14 Nov. 2022, [Peer-reviewed], [Domestic magazines]
  English, Scientific journal, Cartilaginous fishes have various unique physiological features such as a cartilaginous skeleton and a urea-based osmoregulation strategy for adaptation to their marine environment. Also, because they are a sister group of bony vertebrates, understanding their unique features is important from an evolutionary perspective. However, genetic engineering based on gene functions as well as cellular behavior has not been effectively utilized in cartilaginous fishes. This is partly because their reproductive strategy involves internal fertilization, which results in difficulty in microinjection into fertilized eggs at the early developmental stage. Here, to identify efficient gene transfer methods in cartilaginous fishes, we examined the effects of various methods both in vitro and in vivo using the cloudy catshark, a candidate model cartilaginous fish species. In all methods, green fluorescent protein (GFP) expression was used to evaluate exogenous gene transfer. First, we examined gene transfer into primary cultured cells from cloudy catshark embryos by lipofection, polyethylenimine (PEI) transfection, adenovirus infection, baculovirus infection, and electroporation. Among the methods tested, lipofection, electroporation, and baculovirus infection enabled the successful transfer of exogenous genes into primary cultured cells. We then attempted in vivo transfection into cloudy catshark embryos by electroporation and baculovirus infection. Although baculovirus-injected groups did not show GFP fluorescence, electroporation successfully introduced GFP into muscle cells. Furthermore, we succeeded in GFP transfer into adult tissues by electroporation. The in vitro and in vivo gene transfer methods that worked in this study may open ways for genetic manipulation including knockout experiments and cellular lineage analysis in cartilaginous fishes.
• Changes in Ovulation-Related Gene Expression during Induced Ovulation in the Amur Sturgeon (Acipenser schrenckii) Ovarian Follicles
  Ryohei Surugaya; Yuya Hasegawa; Shinji Adachi; Shigeho Ijiri
  International Journal of Molecular Sciences, 23, 21, 13143, 13143, MDPI AG, 29 Oct. 2022, [Peer-reviewed], [Invited], [Last author, Corresponding author]
  Scientific journal, The luteinizing hormone (LH) and maturation-inducing steroids (MIS), such as 17α,20β-dihydroxy-4-pregnen-3-one, regulate the final oocyte maturation in teleosts. Oocyte maturational competence (OMC) and ovulatory competence measure the sensitivity to MIS for oocyte maturation and ovulation, respectively. However, the molecular mechanisms underlying the acquisition of ovulatory competence remain unknown. Sturgeons are an excellent research model for investigating these mechanisms. We examined the seasonal profiles of OMC and ovulatory competence in vitro and the expression of 17 ovulation-related gene candidates using quantitative PCR in Amur sturgeon ovarian follicles. The ovulatory competence was induced by the LH-releasing hormone analog (LHRHa) priming injection after acquiring the OMC, which was spontaneously induced in spring or autumn. Seven genes, including the tissue-type plasminogen activator (plat), were enhanced following the LHRHa priming injection in ovarian follicles sampled from anovulated and ovulated fish. The activin receptor type 1 (acvr1) and prostaglandin G/H synthase 2 (ptgs2) were only upregulated in ovulated fish. Our results suggest that plat/plasmin and prostaglandin (PG)/PG receptor systems are essential for sturgeon ovulation, similar to other vertebrates. Notably, successful ovulation depends on a sufficient PG synthesis, and mediators activating the PG/PG receptor system are essential for acquiring the ovulatory competence. We provide the first report of ovulation-related gene alterations in the ovarian follicles of Amur sturgeons.
• Morphological and molecular gonadal sex differentiation in wild Japanese eel Anguilla japonica
  Horiuchi M; Hagihara S; Kume M; Chushi D; Hasegawa Y; Itakura H; Yamashita Y; Adachi S; Ijiri S
  Cells, 11, 9, e1554, May 2022, [Peer-reviewed], [Invited], [Last author, Corresponding author]
  English, Scientific journal
• Regulation by Progestins, Corticosteroids, and RU486 of Transcriptional Activation of Elephant Shark and Human Progesterone Receptors: An Evolutionary Perspective.
  Xiaozhi Lin; Wataru Takagi; Susumu Hyodo; Shigeho Ijiri; Yoshinao Katsu; Michael E Baker
  ACS pharmacology & translational science, 5, 2, 52, 61, 11 Feb. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal, We investigated progestin and corticosteroid activation of the progesterone receptor (PR) from elephant shark, a cartilaginous fish belonging to the oldest group of jawed vertebrates. Comparison with the human PR provides insights into the evolution of steroid activation of the human PR. At 1 nM steroid, the elephant shark PR is activated by progesterone, 17-hydroxy-progesterone, 20β-hydroxy-progesterone, 11-deoxycorticosterone (21-hydroxyprogesterone), and 11-deoxycortisol. The human PR, in comparison, is activated at 1 nM steroid, only by progesterone and 11-deoxycorticosterone, indicating increased progestin and corticosteroid specificity during the evolution of the human PR. RU486, an important clinical antagonist of the human PR, did not inhibit progesterone activation of the elephant shark PR. Cys-528 in the elephant shark PR corresponds to Gly-722 in the human PR, which is essential for RU486 inhibition of the human PR. Confirming the importance of Cys-528 in the elephant shark PR, RU486 inhibited progesterone activation of the Cys528Gly mutant PR. To investigate the physiological relevance of Gly-722 in the human PR and Cys-528 in the elephant shark PR, we studied steroid activation of the Gly722Cys human PR and Cys528Gly elephant shark PR. Compared to the wild-type human PR, there was an increase in the activation of human Gly722Cys PR by11-deoxycortisol and a decrease in activation by corticosterone, which may have been important in selection for the mutation corresponding to the human glycine-722 PR that first evolved in the platypus PR, a basal mammal.
• Regulation of 17α-Hydroxyprogesterone Production during Induced Oocyte Maturation and Ovulation in Amur Sturgeon (Acipenser schrenckii)
  Yuya Hasegawa; Ryohei Surugaya; Shinji Adachi; Shigeho Ijiri
  Journal of Marine Science and Engineering, 10, 1, 86, 86, MDPI AG, 10 Jan. 2022, [Peer-reviewed], [Invited], [Last author, Corresponding author]
  Scientific journal, In several teleosts, 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) has been identified as a maturation-inducing steroid. DHP is synthesized from 17α-hydroxyprogesterone (17OHP) by 17β-hydroxysteroid dehydrogenase type 12-like (hsd17b12L). Along with 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (3β-HSD), 17α-hydroxylase and C17-20 lyase are associated with 17OHP production. This study aimed to determine the roles of Amur sturgeon hsd3b, P450c17-I (cyp17a1), and P450c17-II (cyp17a2) in 17OHP production and to examine their enzyme activity and mRNA expression pattern during oocyte maturation. In the sturgeons used in this study, hsd3b encoded 3β-HSD, cyp17a1 catalyzed 17α-hydroxylase production with C17-20 lyase activity, and cyp17a2 processed 17α-hydroxylase activity alone. In the ovarian follicles of individuals that underwent induced ovulation, hsd3b mRNA levels increased rapidly, cyp17a1 expression was downregulated, and cyp17a2 expression was upregulated during oocyte maturation. Finally, an in vitro study revealed that salmon pituitary extract (SPE) stimulation rapidly induced hsd3b expression, whereas cyp17a1 expression was downregulated. In vitro, cyp17a2 expression did not rapidly increase with SPE stimulation. This rapid upregulation of hsd3b during oocyte maturation was first observed in teleosts. It was suggested that hsd17b12L expression is upregulated after 17OHP production, which is regulated by hsd3b, cyp17a1, and cyp17a2, resulting in DHP production.
• 17β-hydroxysteroid dehydrogenase type 12-like is associated with maturation-inducing steroid synthesis during induced oocyte maturation and ovulation in sturgeons
  Yuya Hasegawa; Shigeho Ijiri; Ryohei Surugaya; Ryuichi Sakai; Shinji Adachi
  Aquaculture, 546, 737238, 737238, Elsevier BV, Jan. 2022, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Effect of diet on faecal testosterone metabolite levels in a northern fur seal (Callorhinus ursinus) expressed as ash-free dry weight.
  Mayuko Otsuki; Kaoru Kohyama; Wataru Goshima; Motoki Kobayashi; Yuya Hasegawa; Yuka Morita; Shigeho Ijiri; Yoko Mitani
  Coastal Marine Science, 44, 1, 1, 6, International Coastal Research Center, Atmosphere and Ocean Research Institute, the University of Tokyo, Jun. 2021, [Peer-reviewed]
  English, Scientific journal
• Gonadal expression profiles of sex-specific genes during early sexual differentiation in Japanese eel Anguilla japonica
  Hiroyuki Inaba; Seiji Hara; Moemi Horiuchi; Shigeho Ijiri; Takeshi Kitano
  FISHERIES SCIENCE, 87, 2, 203, 209, Mar. 2021, [Peer-reviewed]
  English, Scientific journal
• Histological evidence of multiple spawning in wild Japanese eel Anguilla japonica.
  Akio Shimizu; Shigeho Ijiri; Hikari Izumi; Koichiro Gen; Hiroaki Kurogi; Hiroshi, Hashimoto; Hideki Tanaka; Tadao Jinbo; Hiroaki Saito; Seinen Chow
  Zoological Studies, 60, 61, 2021, [Peer-reviewed]
  English
• Testosterone levels in hair of free-ranging male northern fur seals (Callorhinus ursinus) in relation to sampling month, age class and spermatogenesis
  Mayuko Otsuki; Takanori Horimoto; Motoki Kobayashi; Yuka Morita; Shigeho Ijiri; Yoko Mitani
  Conservation Physiology, 9, 1, coab031, Oxford University Press (OUP), 01 Jan. 2021, [Peer-reviewed], [International Magazine]
  English, Scientific journal,
  Information about the reproductive status of free-ranging pinnipeds provides useful insight into their population dynamics, which is essential to their management and conservation. To determine the reproductive status of individual animals, blood sampling is often required despite being impractical to collect in open water. Hair as an endocrine marker has been used to less invasively assess the reproductive status of terrestrial animals. However, it is unknown whether pinniped reproductive status can be assessed from hair samples. Here, we examine testosterone levels in hair obtained from 57 male northern fur seals and used it to compare their age class and spermatogenesis during the non-breeding season off Hokkaido. We isolated testosterone from the samples using gas chromatography and measured testosterone levels using time-resolved fluoroimmunoassay. Testosterone levels in hair increased towards the breeding season. In May, testosterone levels were the highest in seals aged between 4 and 7 years, followed by those over the age of 8 years and under the age of 4 years. Spermatids, the final phase of spermatogenesis, were present in the seals sampled between April and June, even though testosterone levels were low in April. The seals with spermatids in May showed the highest testosterone levels. Our results demonstrate that seals with higher testosterone levels in May are likely to be mature males (≥4 years). Since hair can be collected using biopsy darts in the field, it will be possible to less invasively determine testosterone levels of male seals in the future.
• 17 beta-Hydroxysteroid dehydrogenase type 12a responsible for testicular 11-ketotestosterone synthesis in the Japanese eel, Anguilla japonica
  Hiroshi Suzuki; Yuichi Ozaki; Shigeho Ijiri; Koichiro Gen; Yukinori Kazeto
  JOURNAL OF STEROID BIOCHEMISTRY AND MOLECULAR BIOLOGY, 198, Apr. 2020, [Peer-reviewed]
  English, Scientific journal
• Non-invasive monitoring of faecal testosterone metabolites expressed in unit per ash-free dry weight in a northern fur seal (Callorhinus ursinus).
  Mayuko Otsuki; Kaoru Kohyama; Wataru Goshima; Motoki Kobayashi; Yuya Hasegawa; Yuka Morita; Shigeho Ijiri; Yoko Mitani
  Japanese Journal of Zoo and Wildlife Medicine, 25, 1, 29, 34, 2020, [Peer-reviewed]
  English, Scientific journal
• 17 beta-Hydroxysteroid dehydrogenase type 12 is responsible for maturation-inducing steroid synthesis during oocyte maturation in Nile tilapia
  Chak Aranyakanont; Shigeho Ijiri; Yuya Hasegawa; Shinji Adachi
  GENERAL AND COMPARATIVE ENDOCRINOLOGY, 290, 2020, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Reproductive physiological characteristics of tropical Celebes eels Anguilla celebesensis in relation to downstream migration and ovarian development
  Hagihara Seishi (corresponding author); Aoyama J; Sudo R; Limbong D; Ijiri S; Adachi S; Tsukamoto K
  Journal of Fish Biology, in press, 3, 558, 569, Wiley, 2020, [Peer-reviewed]
  English, Scientific journal
• Changes in Sex Steroids and Ovarian Steroidogenic Enzyme mRNA Levels in Artificially Maturing Japanese Eel (Anguilla japonica) and Naturally Maturing New Zealand Longfin Eel (Anguilla dieffenbachii) during Vitellogenesis
  Hajime Matsubara; P. Mark Lokman; Yukinori Kazeto; Hiromi Okumura; Shigeho Ijiri; Toshiaki Hirai; Graham Young; Shinji Adachi; Kohei Yamauchi
  FISHES, 4, 4, Dec. 2019, [Peer-reviewed], ［Internationally co-authored］
  English, Scientific journal
• II-2. Sex differentiation in Nile tilapia, Sturgeon and Japanese eel
  Shigeho Ijiri; Shinji Adachi
  Nippon Suisan Gakkaishi (Japanese Edition), 85, 2, 191, Nihon Suisan Gakkai, 2019
  Japanese, Scientific journal
• Sex determination, sex differentiation and sex change in fishes: Past, present and future
  Kiyoshi Kikuchi; Shigeho Ijiri; Takeshi Kitano
  Nippon Suisan Gakkaishi (Japanese Edition), 85, 2, 185, Nihon Suisan Gakkai, 2019
  Japanese, Scientific journal
• Involvement of 11-ketotestosterone in hooknose formation in male pink salmon (Oncorhynchus gorbuscha) jaws
  Hideaki Kudo; Tomoaki Kimura; Yuya Hasegawa; Takashi Abe; Masaki Ichimura; Shigeho Ijiri
  General and Comparative Endocrinology, 260, 41, 50, Academic Press Inc., 01 May 2018, [Peer-reviewed]
  English, Scientific journal
• First report of the occurrence of a female Amur sturgeon Acipenser schrenckii in advanced stages of oogenesis, off the coast of Mombetsu, Hokkaido, Japan.
  Seishi Hagihara; Noriko Azuma; Kiichi Suyama; Seiji Katakura; Shigeho Ijiri; Shinji Adachi
  Coastal Marine Science, 41, 1, 7, 10, 2018, [Peer-reviewed]
  English, Research institution
• Expression pattern of foxl2 and dmrt1 in gonad of Amur sturgeon Acipenser schrenckii in relation to sex differentiation
  Hatsumi Okada; Seishi Hagihara; Katsumasa Yamashita; Shigeho Ijiri; Shinji Adachi
  AQUACULTURE, 479, 1, 712, 720, Oct. 2017, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• 17 beta-HSD Type 12-Like Is Responsible for MaturationInducing Hormone Synthesis During Oocyte Maturation in Masu Salmon
  Shigeho Ijiri; Yasushi Shibata; Nonoha Takezawa; Yukinori Kazeto; Naoki Takatsuka; Erika Kato; Seishi Hagihara; Yuichi Ozaki; Shinji Adachi; Kohei Yamauchi; Yoshitaka Nagahama
  ENDOCRINOLOGY, 158, 3, 627, 639, Mar. 2017, [Peer-reviewed], [Lead author]
  English, Scientific journal
• In vitro 11-ketotestosterone production by the ovary of the Japanese eel, Anguilla japonica.
  Yuya Hasegawa; P Mark Lokman; Shigeho Ijiri; Shinji Adachi
  Simposium Proceedings in “Fisheries Science for Future Generations”, Article number 06009, 2017
  English, International conference proceedings
• Detection of Japanese Eel Endothelial Cells-infecting Virus (JEECV) in Mature Japanese Eel Anguilla japonica Caught from Their Spawning Area
  Sachiko Okazaki-Terashima; Hiroaki Kurogi; Seinen Chow'; Toshihiro Yamamoto; Noriaki Matsuya; Shigeho Ijiri; Noritaka Mochioka; Shinobu Tsuchiakat; Yuki Naoi; Kaori Sano; Tsutomu Omatsu; Shin-ichi Ono; Hiroshi Kuwada; Tetsuya Mizutani
  FISH PATHOLOGY, 51, 2, 64, 66, Jun. 2016, [Peer-reviewed]
  English, Scientific journal
• Quantitative comparisons of maternal transcripts related to cell division between good and poor quality eggs from artificially matured Japanese eel Anguilla japonica.
  Izumi H; Gen K; Horiuchi M; Matsuya N; Ijiri S; Adachi S
  Aquaculture Science, 64, 1, 29, 42, Mar. 2016, [Peer-reviewed]
  English, Scientific journal, The current method of artificial egg production in Japanese eel does not always yield good quality eggs, but the molecular basis for the decrease in egg quality remains unclear. In this study, we compared the levels of 74 maternal transcripts related to cell division among good quality eggs, developing poor quality eggs (i.e., those producing a viable morula embryo without hatching), and non-developing poor quality eggs (i.e., developmentally incompetent eggs) to determine the molecular characteristics of poor quality eggs produced by artificially matured Japanese eel. Only one transcript (lsm7) had a lower level in developing poor quality than in good quality eggs, with the others being present at similar levels between the two types of egg. The levels of 11 transcripts (e.g., cdc26, psma7) were lower in non-developing poor quality than in good quality eggs. These results suggest that insufficient or reduced levels of maternal mRNA related to cell division are associated with the loss of egg quality in artificially matured Japanese eel, and that maternal characteristics other than quantity may affect the developmental competence of poor quality eggs.
• Gonadal soma-derived factor (gsdf), a TGF-beta superfamily gene, induces testis differentiation in the teleost fish Oreochromis niloticus
  Hiroyo Kaneko; Shigeho Ijiri; Tohru Kobayashi; Hikari Izumi; Yuki Kuramochi; De-Shou Wang; Shouta Mizuno; Yoshitaka Nagahama
  MOLECULAR AND CELLULAR ENDOCRINOLOGY, 415, C, 87, 99, Nov. 2015, [Peer-reviewed]
  English, Scientific journal
• Characterization and expression of cDNAs encoding P450c17-II (cyp17a2) in Japanese eel during induced ovarian development
  Ting Su; Shigeho Ijiri; Hirokazu Kanbara; Seishi Hagihara; De-Shou Wang; Shinji Adachi
  GENERAL AND COMPARATIVE ENDOCRINOLOGY, 221, 134, 143, Sep. 2015, [Peer-reviewed], [Corresponding author], ［Internationally co-authored］
  English, Scientific journal
• Sexual characteristics of high-temperature sterilized male Mozambique tilapia, Oreochromis mossanbicus.
  Nakamura M; Nozu R; Ijiri S; Kobayashi T; Hirai T; Yamaguchi Y; Seale A; Lerner DT; Grau GE
  Zoological Letters, 1, 21, 1, 7, Jun. 2015, [Peer-reviewed], [International Magazine]
  English, Scientific journal, INTRODUCTION: In order to clarify the effect of extremely high temperature on gonads of fish, juveniles of the Mozambique tilapia, Oreochromis mossambicus, at three days after hatching (d.a.h.) were reared at a high temperature (37 ± 0.5 °C) for 50 days. The heat-treated fish were then cultivated at a normal water temperature for over six months. RESULTS: The testes of all individuals heat-treated for 50 days were sterile. Histological analysis revealed the complete absence of all stages of spermatogenic germ cells in the testes of the heat-treated males; however, structures within a layer of epithelial cells lining the efferent ducts were observed to actively secrete sperm fluid into the ducts, as in the mature testes of normal males. Clusters of cells immunopositive against P450scc and 3β-hydroxysteroid dehydrogenase were observed in the sterilized testes. Leydig cells had developed smooth endoplasmic reticulum and several mitochondria with tubular cristae indicating active steroidogenesis. The sterilized males displayed male nuptial coloration, actively dug spawning nests, and mated with normal mature females. However, females mated with these males initially brooded their eggs normally but released them prematurely at 4-5 days. All the released eggs were unfertilized and dead. CONCLUSION: Heat-sterilized male tilapia matures endocrinologically but completely lacks spermatogenic germ cells.
• Histological characteristics of the oocyte chorion in wild post-spawning and artificially matured Japanese eels Anguilla japonica
  Hikari Izumi; Seishi Hagihara; Hiroaki Kurogi; Seinen Chow; Katsumi Tsukamoto; Hirohiko Kagawa; Hideaki Kudo; Shigeho Ijiri; Shinji Adachi
  FISHERIES SCIENCE, 81, 2, 321, 329, Mar. 2015, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Selective depletion of rebosomal RNA from total RNA for next-generation sequencing analysis of maternal mRNA in eggs of the Japanese eel, Anguilla japonica
  Izumi H; Hagihara S; Gen K; Ijiri S; Adachi S
  Bulletin of Fisheries Sciences, 65, 3, 125, 130, 北海道大学大学院水産科学研究院, 2015
  Japanese, Research institution, Removal of ribosomal RNAs(rRNA) from total RNA in eggs before preparation of a RNA library is required for the analysis of maternal mRNA using next-generarion sequencing ; this mRNA is essential for normal development. In mammals, the rRNA-depletion method is well-established and is already being used for the development of experiment kits. However, this method is not designed for other species, e.g., non-model organisms. In the current study, we attempted to remove rRNA from total RNA of Japanese eel Anguilla japonica, which is one of the most important aquaculture species in Japan. Removal was performed via hibridization-selection using mammalian probes from a commmercially available kit and/or an ordinally designed eel probe. Quantitative polymerase chain reaction(PCR) was performed to examine the depletion efficiency of 18S rRNA and 28S rRNA were comparative between each method, and >98% depletion was achieved. In addition, RNA-sequencing analysis using a next-generation sequencer and read-mapping analysis were carried out using the rRNA-depleted RNA, which was prepared using a mammalian probe, and mapping analysis revealed that rRNA reads were <1% of the total reads. These results suggest that an rRNA-depletion kit designed for a mammal can also be used for fish species.
• Morphological and physiological characteristics of an oceanic-migrating Japanese eel, Anguilla japonica off Fukushima, Japan.
  Matsuya N; Hagihara S; Wada T; Ijiri S; Adachi S
  Coastal Marine Science, 38, 1, 8, 11, International Coastal Research Center, Atmosphere and Ocean Research Institute, the University of Tokyo, 2015, [Peer-reviewed]
  English, Scientific journal, A female silver Japanese eel Anguilla japonica (681 mm TL) was captured by bottom trawl off Fukushima on 18 October 2013. This is the first report of an oceanic-migrating Japanese eel in the western North Pacific Ocean off northern Japan. We described the status of the silvering stage, morphological characteristics, age, developmental stage of the ovaries, and the serum levels of sex steroids for the eel. The GSI of the eel was 2.33 and the mean diameter of the largest group of oocytes was 269.9 μm and these were at the early vitellogenic stage. The serum E2 level was 3.9 ng/ml and 11-KT was 17.9 ng/ml. These steroid levels were higher than the mean steroid levels of female silver eels captured in Hamana Lake, but other morphological and physiological characteristics of the eel were not much different from those of silver eels captured in river, estuary, and coastal waters.
• Identification of genes involved in gonadal sex differentiation and the dimorphic expression pattern in undifferentiated gonads of Russian sturgeon Acipenser gueldenstaedtii Brandt & Ratzeburg, 1833
  S. Hagihara; R. Yamashita; S. Yamamoto; M. Ishihara; T. Abe; S. Ijiri; S. Adachi
  JOURNAL OF APPLIED ICHTHYOLOGY, 30, 6, 1557, 1564, Dec. 2014, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• Seasonal changes in oocyte maturational competence, ovulatory competence and gonadotropin sensitivity of ovarian follicles in hybrid sturgeon, bester (Huso huso x Acipenser ruthenus)
  M. Ishihara; B. Tokui; T. Abe; S. Ijiri; S. Adachi
  JOURNAL OF APPLIED ICHTHYOLOGY, 30, 6, 1141, 1148, Dec. 2014, [Peer-reviewed]
  English, Scientific journal
• Development and partial characterisation of an antiserum against apolipoprotein B of the short-finned eel, Anguilla australis
  Erin L. Damsteegt; Hiroko Mizuta; Yuichi Ozaki; Naoshi Hiramatsu; Takashi Todo; Akihiko Hara; Shigeho Ijiri; Shinji Adachi; P. Mark Lokman
  JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY, 184, 5, 589, 599, Jul. 2014, [Peer-reviewed], ［Internationally co-authored］
  English, Scientific journal
• Characterization of phase-II conjugation reaction of polycyclic aromatic hydrocarbons in fish species: unique pyrene metabolism and species specificity observed in fish species.
  Yoshinori Ikenaka; Mami Oguri; Aksorn Saengtienchai; Shouta M M Nakayama; Shigeho Ijiri; Mayumi Ishizuka
  Environmental toxicology and pharmacology, 36, 2, 567, 578, 2, Sep. 2013, [Peer-reviewed], [International Magazine]
  English, Metabolic activity, particularly conjugation, was examined in fish by analyzing pyrene (a four-ring, polycyclic aromatic hydrocarbon) metabolites using high-performance liquid chromatography (HPLC) with fluorescence detector (FD), a mass spectrometry (MS) system, and kinetic analysis of conjugation enzymes. Fourteen fresh water fish species, including Danio rerio and Orizias latipes, were exposed to aqueous pyrene, and the resulting metabolites were collected. Identification of pyrene metabolites by HPLC/FD and ion-trap MS indicated that the major metabolites were pyrene glucuronide and pyrene sulfate in all 14 species. Differences were observed in pyrene glucuronide:pyrene sulfate ratio and in the total amount of pyrene conjugates excreted between fish species. Furthermore, a correlation was found between the amount of pyrene glucuronide present and the total amount of the pyrene metabolite eliminated. Kinetic analysis of conjugation by hepatic microsomes in vitro indicated that the differences in excreted metabolites reflected the differences in enzymatic activities.
• Geographic information system-based source estimation of copper pollution in Lake Itezhi-tezhi and metal-accumulation profiles in Oreochromis spp. from both field and laboratory studies.
  Shouta M M Nakayama; Yoshinori Ikenaka; Kaampwe Muzandu; Kennedy Choongo; John Yabe; Taro Muroya; Shigeho Ijiri; Masao Minagawa; Takashi Umemura; Mayumi Ishizuka
  Archives of environmental contamination and toxicology, 64, 1, 119, 29, 1, Jan. 2013, [Peer-reviewed], [International Magazine]
  English, The Copperbelt region, upstream of the Kafue River, including Lake Itezhi-tezhi (ITT), in Zambia has extensive copper (Cu) mines. In our field study, geographic information system analysis in lake sediment indicated that the northern part of the lake, i.e., the Copperbelt region, could be the source of Cu pollution. Concentrations of Cu in stomach contents between fish species were not significantly different. However, Oreochromis spp. liver showed significantly greater Cu concentrations than those in other fish species. Log liver [Cu], standard length, and nitrogen stable isotope ratio were positively correlated only in Oreochromis spp. In the laboratory study, O. niloticus and O. latipes were exposed to Cu for 4 days, and recovery phases ≤ 28 days were examined. O. niloticus showed significantly greater concentrations of Cu compared with O. latipes at all sampling points. Significantly greater concentrations of Hg in Schilbe intermedius liver than for other fish species were observed, whereas O. macrochir showed significantly greater concentrations of cadmium. In conclusion, the northern part of the lake could be the source of Cu pollution in Lake ITT. Diet may not be the reason for high Cu accumulation in Oreochromis spp. Results from both field and laboratory studies imply that Oreochromis spp. contain high concentrations of Cu under normal physiological conditions.
• Expression Patterns of Gonadotropin Hormones and Their Receptors During Early Sexual Differentiation in Nile Tilapia Oreochromis niloticus
  Hongwei Yan; Shigeho Ijiri; Quan Wu; Tohru Kobayashi; Shuang Li; Taro Nakaseko; Shinji Adachi; Yoshitaka Nagahama
  BIOLOGY OF REPRODUCTION, 87, 5, 116, Nov. 2012, [Peer-reviewed], [Corresponding author]
  English, Scientific journal
• 11-ketotestosterone Synchronously Induces Oocyte Development and Silvering-related Changes in the Japanese Eel, Anguilla japonica
  Ryusuke Sudo; Ryota Tosaka; Shigeho Ijiri; Shinji Adachi; Jun Aoyama; Katsumi Tsukamoto
  ZOOLOGICAL SCIENCE, 29, 4, 254, 259, Apr. 2012, [Peer-reviewed]
  English, Scientific journal
• Ovarian steroidogenesis and the role of sex steroid hormones on ovarian growth and maturation of the Japanese eel
  Yukinori Kazeto; Ryota Tosaka; Hajime Matsubara; Shigeho Ijiri; Shinji Adachi
  JOURNAL OF STEROID BIOCHEMISTRY AND MOLECULAR BIOLOGY, 127, 3-5, 149, 154, Nov. 2011, [Peer-reviewed], [Invited]
  English, Scientific journal
• Effect of temperature decrease on oocyte development, sex steroids, and gonadotropin beta-subunit mRNA expression levels in female Japanese eel Anguilla japonica
  Ryusuke Sudo; Ryota Tosaka; Shigeho Ijiri; Shinji Adachi; Hiroaki Suetake; Yuzuru Suzuki; Noriyuki Horie; Satoru Tanaka; Jun Aoyama; Katsumi Tsukamoto
  FISHERIES SCIENCE, 77, 4, 575, 582, Jul. 2011, [Peer-reviewed]
  English, Scientific journal
• Effect of temperature decrease on oocyte development, sex steroids, and gonadotropin beta-subunit mRNA expression levels in female Japanese eel Anguilla japonica
  Ryusuke Sudo; Ryota Tosaka; Shigeho Ijiri; Shinji Adachi; Hiroaki Suetake; Yuzuru Suzuki; Noriyuki Horie; Satoru Tanaka; Jun Aoyama; Katsumi Tsukamoto
  FISHERIES SCIENCE, 77, 4, 575, 582, Jul. 2011, [Peer-reviewed]
  English, Scientific journal
• Controlled reproduction in the Japanese eel (Anguilla japonica), past and present
  Ijiri Shigeho; Tsukamoto Katsumi; Chow Seinen; Kurogi Hiroaki; Adachi Shinji; Tanaka Hideki
  Aquaculture Europe, 36, 2, 13, 17, the European Aquaculture Society, Jun. 2011, [Invited]
  English, Scientific journal, The Japanese eel, Anguilla japonica, is one of the mostimportant species of the aquaculture industry of EastAsia. Supply of glass eels for aquaculture is completely dependent on wild catch. However, glass-eel catches in Japan declined linearly from over 200 tons in the early 1960s to 20 tons at present. In recent years an unstable situation has occurred with glass-eel catches not meeting the demand of aquaculture farms. In order to address this rapid decline, a challenging research project for artificialproduction of glass eels was commenced in the late 1960s.Since then, through a continuing process of trial anderror, the production of second-generation larvae wasfinally achieved in 2010. Throughout the research, a new application of several substances has caused breakthroughs in artificial induction of sexual maturation and larvae rearing. This article reports on a study of controlled eel reproduction focusing onthe finding of substances that accelerated progress. Inaddition, guideline research on eel reproduction in thewild was conducted aiming at overcoming currentbottlenecks that impeded the establishment of largescale glass-eel production in captivity, by investigating maturing eels and eggs collected in their spawning area in the vicinity of the West Mariana Ridge.
• Androgens and Very Low Density Lipoprotein Are Essential for the Growth of Previtellogenic Oocytes from Japanese Eel, Anguilla japonica, In Vitro
  Taku Endo; Takashi Todo; P. Mark Lokman; Hideaki Kudo; Shigeho Ijiri; Shinji Adachi; Kohei Yamauchi
  BIOLOGY OF REPRODUCTION, 84, 4, 816, 825, Apr. 2011, [Peer-reviewed]
  English, Scientific journal
• Oceanic spawning ecology of freshwater eels in the western North Pacific
  Katsumi Tsukamoto; Seinen Chow; Tsuguo Otake; Hiroaki Kurogi; Noritaka Mochioka; Michael J. Miller; Jun Aoyama; Shingo Kimura; Shun Watanabe; Tatsuki Yoshinaga; Akira Shinoda; Mari Kuroki; Machiko Oya; Tomowo Watanabe; Kazuhiro Hata; Shigeho Ijiri; Yukinori Kazeto; Kazuharu Nomura; Hideki Tanaka
  NATURE COMMUNICATIONS, 2, 179, Feb. 2011, [Peer-reviewed]
  English, Scientific journal
• Eel and sturgeon, unmanageable species in seeding production.
  IJIRI Shigeho
  Nippon Suisan Gakkaishi, 36, 13, 17, 2011
  Japanese
• Expression of androgen receptor mRNA in the ovary of Japanese eel, Anguilla japonica, during artificially induced ovarian development
  Ryota Tosaka; Takashi Todo; Yukinori Kazeto; P. Mark Lokman; Shigeho Ijiri; Shinji Adachi; Kohei Yamauchi
  GENERAL AND COMPARATIVE ENDOCRINOLOGY, 168, 3, 424, 430, Sep. 2010, [Peer-reviewed]
  English, Scientific journal
• The Relationship between the Developmental Stage of Oocytes in Various Seasons and the Quality of the Egg Obtained by Artificial Maturation in the Feminized Japanese Eel Anguilla japonica
  CHAI YU; TOSAKA RYOTA; ABE TOMOKI; SAGO KEISUKE; SAGO YOSUKE; HATANAKA ERI; IJIRI SHIGEHO; ADACHI SHINJI
  Aquaculture Science, 58, 2, 269, 278, 水産増殖談話会, Jun. 2010, [Peer-reviewed]
  English, Scientific journal, 雌化ウナギ2歳魚を9月、12月または4月にサケ脳下垂体注射によって人為催熟し、得られる卵質の差を受精率、孵化率および8日後生存率で評価した。9月、12月は比較的良質な卵が得られる傾向が認められたが、4月では卵は得られるものの、その卵質は極めて悪かった。催熟前の卵母細胞を組織学的に観察すると、12月に卵黄形成開始が観察されたが、4月には退行している様子が観察された。4月に催熟を開始しても良質な卵が得られない原因として、催熟前に既に卵母細胞が退行しつつあることが考えられた。以上の結果から、雌化ウナギ2歳魚の人為催熟は9月から12月の間にかけて開始することが良質な卵を得るために適当であると結論された。
• Development of an in vitro culture system for producing eel larvae from immature ovarian follicles in Japanese eel Anguilla japonica
  Tomoki Abe; Shigeho Ijiri; Shinji Adachi; Kohei Yamauchi
  FISHERIES SCIENCE, 76, 2, 257, 265, Mar. 2010, [Peer-reviewed]
  English, Scientific journal
• Effects of reproductive stage, GH, and 11-ketotestosterone on expression of growth differentiation factor-9 in the ovary of the eel, Anguilla australis
  P. M. Lokman; Y. Kazeto; Y. Ozaki; S. Ijiri; R. Tosaka; M. Kohara; S. L. Divers; H. Matsubara; L. G. Moore; S. Adachi
  REPRODUCTION, 139, 1, 71, 83, Jan. 2010, [Peer-reviewed]
  English, Scientific journal
• Molecular Cloning, Characterization, and Evolutionary Analysis of Estrogen Receptors from Phylogenetically Ancient Fish
  Yoshinao Katsu; Satomi Kohno; Susumu Hyodo; Shigeho Ijiri; Shinji Adachi; Akihiko Hara; Louis J. Guillette; Taisen Iguchi
  ENDOCRINOLOGY, 149, 12, 6300, 6310, Dec. 2008, [Peer-reviewed]
  English, Scientific journal
• In vitro induction of oil droplet accumulation into previtellogenic oocytes of Japanese eel, Anguilla japonica
  Taku Endo; Takashi Todo; P. Mark Lokman; Shigeho Ijiri; Shinji Adachi; Kohei Yamauchi
  CYBIUM, 32, 2, 239, 240, Jul. 2008, [Peer-reviewed]
  English, Scientific journal
• Early development of forebrain gonadotrophin-releasing hormone (GnRH) neurones and the role of GnRH as an autocrine migration factor
  E. Abraham; O. Palevitch; S. Ijiri; S. J. Du; Y. Gothilf; Y. Zohar
  JOURNAL OF NEUROENDOCRINOLOGY, 20, 3, 394, 405, Mar. 2008, [Peer-reviewed]
  English, Scientific journal
• Sexual dimorphic expression of genes in gonads during early differentiation of a teleost fish, the Nile tilapia Oreochromis niloticus
  Shigeho Ijiri; Hiroyo Kaneko; Tohru Kobayashi; De-Shou Wang; Fumie Sakai; Bindhu Paul-Prasanth; Masaru Nakamura; Yoshitaka Nagahama
  BIOLOGY OF REPRODUCTION, 78, 2, 333, 341, Feb. 2008, [Peer-reviewed], [Lead author]
  English, Scientific journal
• The effect of female presence upon serum levels of vitellogenin in male Japanese whiting Sillago japonica
  Komei Hotta; Takayuki Watanabe; Chiho Kishida; Yukio Nakamura; Shigeho Ijiri; Shinji Adachi; Kohei Yamauchi
  NIPPON SUISAN GAKKAISHI, 74, 1, 20, 25, Jan. 2008, [Peer-reviewed]
  Japanese, Scientific journal
• Liver receptor homologue-1 (LRH-1) activates the promoter of brain aromatase (cyp19a2) in a Teleost fish, the Medaka, Oryzias latipes
  Yuki Ohmuro-Matsuyama; Kataaki Okubo; Masaru Matsuda; Shigeho Ijiri; Deshou Wang; Guijun Guan; Taiga Suzuki; Makoto Matsuyama; Ken-Ichiro Morohashi; Yoshitaka Nagahama
  MOLECULAR REPRODUCTION AND DEVELOPMENT, 74, 9, 1065, 1071, Sep. 2007, [Peer-reviewed]
  English, Scientific journal
• Foxl2 up-regulates aromatase gene transcription in a female-specific manner by binding to the promoter as well as interacting with Ad4 binding protein/steroidogenic factor 1
  De-Shou Wang; Tohru Kobayashi; Lin-Yan Zhou; Bindhu Paul-Prasanth; Shigeho Ijiri; Fumie Sakai; Kataaki Okubo; Ken-ichirou Morohashi; Yoshitaka Nagahama
  MOLECULAR ENDOCRINOLOGY, 21, 3, 712, 725, Mar. 2007, [Peer-reviewed]
  English, Scientific journal
• Sex determination and gonadal sex differentiation in fish
  IJIRI Shigeho
  ホルモンと臨牀, 54, 6, 479, 487, Jun. 2006, [Invited]
  Japanese, Scientific journal
• Molecular biology of ovarian aromatase in sex reversal: Complementary DNA and 5 '-flanking region isolation and differential expression of ovarian aromatase in the Gilthead Seabream (Sparus aurata)
  TT Wong; S Ijiri; Y Zohar
  BIOLOGY OF REPRODUCTION, 74, 5, 857, 864, May 2006, [Peer-reviewed]
  English, Scientific journal
• Cloning and characterization of a cDNA encoding cholesterol side-chain cleavage cytochrome P450 (CYP11A1): Tissue-distribution and changes in the transcript abundance in ovarian tissue of Japanese eel, Anguilla japonica, during artificially induced sexual development
  Y Kazeto; S Ijiri; S Adachi; K Yamauchi
  JOURNAL OF STEROID BIOCHEMISTRY AND MOLECULAR BIOLOGY, 99, 2-3, 121, 128, May 2006, [Peer-reviewed]
  English, Scientific journal
• Changes in localization of cytochrome P450 cholesterol side-chain cleavage (P450scc) in Japanese eel testis and ovary during gonadal development
  S Ijiri; N Takei; Y Kazeto; T Todo; S Adachi; K Yamauchi
  GENERAL AND COMPARATIVE ENDOCRINOLOGY, 145, 1, 75, 83, Jan. 2006, [Peer-reviewed]
  English, Scientific journal
• Specific gene expression in Nile tilapia gonad during sex differentiation.
  Ijiri S; Wang D; Kaneko H; Nagahama Y
  Proceedings of the the 5th international symposium of the Asia and Oceania society for comparative endocrinology, 149, 150, 2006
  English, International conference proceedings
• Changes in Serum Steroid Hormones during Ovarian Development in the Captive Common Japanese Conger Conger myriaster (Brevoort)
  CHIBA Hiroaki; IJIRI Shigeho; IWATA Munehico; NAKAMURA Masaru; ADACHI Shinji; YAMAUCHI Kohei
  Aquaculture Science, 53, 2, 189, 198, 水産増殖談話会, Jun. 2005, [Peer-reviewed]
  English, Scientific journal, マアナゴ雌の周年飼育を行い、卵巣発達過程と血中ステロイドホルモン量の変化を調べた。生殖腺体指数（GSI）は、12月から翌年6月にかけて上昇し、6月に平均4.8のピークに達した後、減少した。卵巣卵は12月から1月にかけて卵黄形成を開始し、GSIの上昇とともに卵黄形成中期まで発達したが、6月以降その大部分の個体は卵黄形成途上で退行した。脳下垂体中のアルデヒドフクシン陽性細胞数は6月まで卵黄形成の進行とともに著しく増加したが、退行卵の増加とともに減少した。エストラジオール－17βは1月の卵黄形成初期にピーク（3.53ng／ml）を迎えた後、減少し低値を維持した。テストステロンは6月の卵巣卵の退行初期に平均7.93ng／ml のピークに達した後、減少した。
• Expression of 20 beta-hydroxysteroid dehydrogenase and P450 17 alpha-hydroxylase/c17-20 lyase during hCG-induced in vitro oocyte maturation in snake head murrel Channa striatus
  G. Sreenivasulu; I. Swapna; M. K. Rasheeda; S. Ijiri; S. Adachi; K. Thangaraj; B. Senthilkumaran
  FISH PHYSIOLOGY AND BIOCHEMISTRY, 31, 2-3, 227, 230, Apr. 2005, [Peer-reviewed]
  English, Scientific journal
• Changes in mRNA levels of ovarian steroidogenic enzymes during artificial maturation of Japanese eel Anguilla japonica
  H Matsubara; Y Kazeto; S Ijiri; T Hirai; S Adachi; K Yamauchi
  FISHERIES SCIENCE, 69, 5, 979, 988, Oct. 2003, [Peer-reviewed]
  English, Scientific journal
• Molecular characterization of the GnRH system in zebrafish (Danio rerio): cloning of chicken GnRH-II, adult brain expression patterns and pituitary content of salmon GnRH and chicken GnRH-II
  C Steven; N Lehnen; K Kight; S Ijiri; U Klenke; WA Harris; Y Zohar
  GENERAL AND COMPARATIVE ENDOCRINOLOGY, 133, 1, 27, 37, Aug. 2003, [Peer-reviewed]
  English, Scientific journal
• Molecular cloning and characterization of 3 beta-hydroxysteroid dehydrogenase/Delta(5)-Delta(4) isomerase cDNAs from Japanese eel ovary
  Y Kazeto; S Ijiri; H Matsubara; S Adachi; K Yamauchi
  JOURNAL OF STEROID BIOCHEMISTRY AND MOLECULAR BIOLOGY, 85, 1, 49, 56, May 2003, [Peer-reviewed]
  English, Scientific journal
• Characterization of a cDNA Encoding P-450 aromatase (CYP19) from Japanese eel ovary and its expression in ovarian follicles during induced ovarian development
  S Ijiri; Y Kazeto; PM Lokman; S Adachi; K Yamauchi
  GENERAL AND COMPARATIVE ENDOCRINOLOGY, 130, 2, 193, 203, Feb. 2003, [Peer-reviewed]
  English, Scientific journal
• Ovarian mitochondrial cytochrome b mRNA levels increase with sexual maturity in freshwater eels (Anguilla spp.)
  PM Lokman; Y Kazeto; S Ijiri; G Young; T Miura; S Adachi; K Yamauchi
  JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY, 173, 1, 11, 19, Feb. 2003, [Peer-reviewed]
  English, Scientific journal
• Effects of rearing water quality on expression of brain corticotropin-releasing hormone and gonadal development in goldfish (Carassius auratus)
  K Nagano; T Kawasaki; S Ijiri; T Todo; S Adachi; K Yamauchi
  FISH PHYSIOLOGY AND BIOCHEMISTRY, 28, 1-4, 437, 438, 2003, [Peer-reviewed]
  English, Scientific journal
• 11-ketotestosterone potentiates estrogen-induced vitellogenin production in liver of Japanese eel (Anguilla japonica)
  H Asanuma; H Ohashi; H Matsubara; S Ijiri; T Matsubara; T Todo; S Adachi; K Yamauchi
  FISH PHYSIOLOGY AND BIOCHEMISTRY, 28, 1-4, 383, 384, 2003, [Peer-reviewed]
  English, Scientific journal
• Synthesis and possible function of 11-ketotestosterone during oogenesis in eel (Anguilla spp.)
  M Matsubara; PM Lokman; A Senaha; Y Kazeto; S Ijiri; A Kambegawa; T Hirai; G Young; T Todo; S Adachi; K Yamauchi
  FISH PHYSIOLOGY AND BIOCHEMISTRY, 28, 1-4, 353, 354, 2003, [Peer-reviewed]
  English, Scientific journal
• Immunolocalization of steroidogenic enzymes (P450scc, P450c17, P450arom) in gonad of Japanese eel
  S Ijiri; N Takei; S Andachi; K Yamauchi
  FISH PHYSIOLOGY AND BIOCHEMISTRY, 28, 1-4, 209, 210, 2003, [Peer-reviewed]
  English, Scientific journal
• The 5 '-flanking regions of CYP19A1 and CYP19A2 in zebrafish
  YK Kazeto; S Ijiri; AR Place; Y Zohar; JM Trant
  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 288, 3, 503, 508, Nov. 2001, [Peer-reviewed]
  English, Scientific journal
• Molecular biology of the channel catfish gonadotropin receptors: 2. Complementary DNA cloning, functional expression, and seasonal gene expression of the follicle-stimulating hormone receptor
  RS Kumar; S Ijiri; JM Trant
  BIOLOGY OF REPRODUCTION, 65, 3, 710, 717, Sep. 2001, [Peer-reviewed]
  English, Scientific journal
• Molecular biology of channel catfish gonadotropin receptors: 1. Cloning of a functional luteinizing hormone receptor and preovulatory induction of gene expression
  RS Kumar; S Ijiri; JM Trant
  BIOLOGY OF REPRODUCTION, 64, 3, 1010, 1018, Mar. 2001, [Peer-reviewed]
  English, Scientific journal
• In vitro effects of gonadotropins on estradiol-17b production by ovarian follicles from Japanese eel.
  Seki S; Abe T; Kazeto Y; Matsubara H; Inaba K; Ijiri S; Adachi S; Yamauchi K
  Proceedings of the international symposium on advances in eel biology, 222, 224, 2001
  English, International conference proceedings
• Changes in the expression of steroidogenic enzyme genes in the Japanese eel ovary during artificial maturation.
  Matsubara H; Kazeto Y; Ijiri S; Abe T; Seki S; Inaba K; Hirai T; Adachi S; Yamauchi K
  Proceedings of the international symposium on advances in eel biology, 213, 215, 2001
  English, International conference proceedings
• Oogenesis in the Japanese eel.
  Adachi S; Ijiri S; Yamauchi K
  Proceedings of the international symposium on advances in eel biology, 66, 64, 2001
  English, International conference proceedings
• Changes in the expression of genes encoding steroidogenic enzymes in the channel catfish (Ictalurus punctatus) ovary throughout a reproductive cycle
  RS Kumar; S Ijiri; JM Trant
  BIOLOGY OF REPRODUCTION, 63, 6, 1676, 1682, Dec. 2000, [Peer-reviewed]
  English, Scientific journal
• Developmental changes in pituitary-thyroid axis, and formation of gonads in leptocephali and glass eels of Anguilla spp.
  Y Ozaki; H Okumura; Y Kazeto; T Ikeuchi; S Ijiri; M Nagae; S Adachi; K Yamauchi
  FISHERIES SCIENCE, 66, 6, 1115, 1122, Dec. 2000, [Peer-reviewed]
  English, Scientific journal
• Cloning of 17 beta-hydroxysteroid dehydrogenase-1 cDNAs from Japanese eel ovary
  Y Kazeto; S Ijiri; H Matsubara; S Adachi; K Yamauchi
  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 279, 2, 451, 456, Dec. 2000, [Peer-reviewed]
  English, Scientific journal
• Cloning and functional expression of a thyrotropin receptor from the gonads of a vertebrate (bony fish): potential thyroid-independent role for thyrotropin in reproduction
  RS Kumar; S Ijiri; K Kight; P Swanson; A Dittman; D Alok; Y Zohar; JM Trant
  MOLECULAR AND CELLULAR ENDOCRINOLOGY, 167, 1-2, 1, 9, Sep. 2000, [Peer-reviewed]
  English, Scientific journal
• Characterization of gonadal and extra-gonadal forms of the cDNA encoding the Atlantic stingray (Dasyatis sabina) cytochrome P450 aromatase (CYP19)
  S Ijiri; C Berard; JM Trant
  MOLECULAR AND CELLULAR ENDOCRINOLOGY, 164, 1-2, 169, 181, Jun. 2000, [Peer-reviewed]
  English, Scientific journal
• Molecular cloning and characterization of Japanese eel ovarian P450c17 (CYP17) cDNA
  Y Kazeto; S Ijiri; T Todo; S Adachi; K Yamauchi
  GENERAL AND COMPARATIVE ENDOCRINOLOGY, 118, 1, 123, 133, Apr. 2000, [Peer-reviewed]
  English, Scientific journal
• The first report of an untranslated exon I in the aromatase gene (CYP19) of a primitive vertebrate
  Ijiri S; Trant JM
  Molecular Steroidogenesis, Frontiers Science Series 29, 327, 328, 1999
  English, Scientific journal
• Molecular cloning of cDNAs encoding steroidogenic enzymes from the ovary of Japanese eel
  Kazeto Y; Ijiri S; Matsubara H; Adachi S; Yamauchi K
  Molecular Steroidogenesis, Frontiers Science Series 29, 323, 326, 1999
  English, Scientific journal
• Molecular studies of steroidogenesis using primitive vertebrates (sharks and rays) as a models
  Trant JM; Ijiri S
  Molecular Steroidogenesis, Frontiers Science Series 29, 313, 316, 1999
  English, Scientific journal
• Comparison of mRNA levels of ovarian steroidogenic enzymes between artificially maturing Japanese and naturally maturing New Zealand eels.
  Matsubara H; Kazeto Y; Lokman P. M; Okumura H; Ijiri S; Young G; Adachi S; Yamauchi K
  Proceedings, the 6th International Symposium on Reproductive Physiology of Fish, 181, 181, 1999
  English, International conference proceedings
• Pretreatment reproductive stage and oocyte development induced by salmon pituitary homogenate in the Japanese eel Anguilla japonica
  S Ijiri; T Kayaba; N Takeda; H Tachiki; S Adachi; K Yamauchi
  FISHERIES SCIENCE, 64, 4, 531, 537, Aug. 1998, [Peer-reviewed]
  English, Scientific journal
• Ovarian development and serum steroid hormone profiles in hatchery-bred female catfish Clarias macrocephalus (Gunther) during an annual reproductive cycle
  JD Tan-Fermin; S Ijiri; H Ueda; S Adachi; K Yamauchi
  FISHERIES SCIENCE, 63, 6, 867, 872, Dec. 1997, [Peer-reviewed]
  English, Scientific journal
• Eel ovarian 20 beta-hydroxysteroid dehydrogenase: molecular cloning and gene expression during artificial maturation of the Japanese eel, Anguilla japonica
  PM Lokman; Y Kazeto; S Ijiri; S Adachi; K Yamauchi
  ADVANCES IN COMPARATIVE ENDOCRINOLOGY, TOMES 1 AND 2, 1517, 1521, 1997
  English, International conference proceedings
• Molecular cloning of the cDNA encoding P450c17 from the Japanese eel ovary and development changes in its expression
  Y Kazeto; S Ijiri; S Adachi; K Yamauchi
  ADVANCES IN COMPARATIVE ENDOCRINOLOGY, TOMES 1 AND 2, 581, 583, 1997
  English, International conference proceedings
• Changes in serum steroid hormones and steroidogenic ability of ovarian follicles during artificial maturation of cultivated Japanese eel, Anguilla japonica
  S Ijiri; Y Kazeto; N Takeda; H Chiba; S Adachi; K Yamauchi
  AQUACULTURE, 135, 1-3, 3, 16, Oct. 1995, [Peer-reviewed]
  English, Scientific journal
• CHANGE OF LIPOVITELLIN DURING IN-VITRO OOCYTE MATURATION IN JAPANESE FLOUNDER PARALICHTHYS-OLIVACEUS
  T MATSUBARA; S ADACHI; S IJIRI; K YAMAUCHI
  FISHERIES SCIENCE, 61, 3, 478, 481, Jun. 1995, [Peer-reviewed]
  English, Scientific journal
• DIURNAL PERIODICITY IN TESTICULAR ACTIVITY IN THE JAPANESE FLOUNDER PARALICHTHYS-OLIVACEUS
  M MATSUYAMA; M YONEDA; H TAKEUCHI; H KAWAGA; M KASHIWAGI; K TABATA; Y NAGAHAMA; S IJIRI; S ADACHI; K YAMAUCHI
  FISHERIES SCIENCE, 61, 1, 17, 23, Feb. 1995, [Peer-reviewed]
  English, Scientific journal

• アムールチョウザメ17β-水酸基脱水素酵素タイプ12-likeの酵素活性および卵成熟期における発現動態
  長谷川祐也; 井尻成保; 駿河谷諒平; 酒井隆一; 足立伸次, 日本水産学会大会講演要旨集(CD-ROM), 2021, 2021
• ニホンウナギ生殖腺における新規性分化関連遺伝子の探索
  堀内萌未; 稲葉駿; 萩原聖士; 板倉光; 山下洋; 久米学; 塚本勝巳; 井尻成保; 足立伸次, 日本水産学会大会講演要旨集(CD-ROM), 2021, 2021
• 5. Fertility and sterility in hybrid sturgeons
  Shigeho Ijiri; Shinji Adachi, Nippon Suisan Gakkaishi (Japanese Edition), 86, 2, 103, 2020
  Nihon Suisan Gakkai, Japanese, Report scientific journal
• 天然ニホンウナギの生殖腺の性分化 口頭
  堀内 萌未; 中司 大智; 長谷川 祐也; 萩原 聖士; 板倉 光; 山下 洋; 久米 学; 寺島 佑樹; 塚本 勝巳; 井尻 成保; 足立 伸次, 東アジア鰻学会第2回研究発表会, 31 Mar. 2019
  Japanese, Summary national conference
• 北海道沿岸における2015年のチョウザメ科魚類の異常漁獲および生殖腺の特徴
  萩原聖士; 須山喜市; 東典子; 堤尚信; 西尾朋高; 市村政樹; 三坂尚行; 鈴木渉太; 宮城大助; 古市明文; 市川卓; 松原創; 川崎琢真; 宗原弘幸; 高橋英祐; 山羽悦郎; 井尻成保; 足立伸次, 日本水産学会大会講演要旨集, 2016, 16, 26 Mar. 2016
  Japanese
• 北海道産チョウザメ類保護と養殖産業化のための種苗生産体制整備
  足立伸次; 井尻成保; 萩原聖士; 三坂尚行; 古市明文; 市村政樹, ノーステック財団 研究開発助成事業2016 成果報告書, 27, 29, 2016
  Japanese, Others
• Transcriptional profiling of olfactory imprinting in the olfactory center of Pacific salmon
  MinowaY; Hagihara S; Abe T; Ijiri S; Adachi S; Kudo H, Chemical Senses, 41, 9, e145, 2016
  English, Summary international conference
• Gonadal soma-derived factorはティラピアの精巣分化を誘導する
  井尻成保; 金子裕代; 泉ひかり; 倉持有希; 水野翔太; 足立伸次; 長濱嘉孝, 日本水産学会大会講演要旨集, 2015, 2015
• Acipenser medirostrisとされている北日本に来遊するチョウザメ属魚類はA.mikadoiである
  萩原聖士; 東典子; 井尻成保; 足立伸次, 日本水産学会大会講演要旨集, 2014, 100, 27 Mar. 2014
  Japanese
• サクラマスの卵成熟誘起ステロイド産生を担う20βHSD遺伝子の同定
  竹澤野葉; 井尻成保; 柴田安司; 風藤行紀; 鈴木博史; 足立伸次; 山内皓平; 長濱嘉孝, 日本水産学会大会講演要旨集, 2013, 2013
• Roles of GTHs in gonadal sex differentiation of Nile tilapla
  YAN Hongwei; IJIRI Shigeho; LI Shuang; ADACHI Shinji; KOBAYASHI Tohru; NAGAHAMA Yoshitaka, 日本水産学会大会講演要旨集, 2013, 2013
• ナイルティラピア遺伝的雄仔魚の雌化誘導に伴う性分化関連遺伝子群の発現変動
  李爽; 井尻成保; ヤン ホンウェイ; 西澤朋実; 足立伸次; 長濱嘉孝, 日本水産学会大会講演要旨集, 2013, 2013
• 自然エネルギーを利用した北方型循環養殖システムの開発
  安部智貴; 加藤良平; 金子拓未; 安井肇; 井尻成保; 足立伸次, 日本水産学会大会講演要旨集, 2012, 118, 26 Mar. 2012
  Japanese
• GSDF(gonadal soma‐derived growth factor)はメダカ遺伝的雌の雄化を引き起こす
  木寺智則; 内川拓; 白石絵吏; 松田勝; 井尻成保; 北野健, 日本水産学会大会講演要旨集, 2012, 34, 26 Mar. 2012
  Japanese
• 自然エネルギーを利用した循環養殖システムの開発
  加藤良平; 安部智貴; 金子拓未; 木村暢夫; 藤森康澄; 安井肇; 井尻成保; 足立伸次, 日本水産学会北海道支部大会講演要旨集, 2011, 58, 2011
  Japanese
• Effects of reproductive stage, GH, and 11-ketotestosterone on expression of growth differentiation factor-9 in the ovary of the eel, Anguilla australis
  P. M. Lokman; Y. Kazeto; Y. Ozaki; S. Ijiri; R. Tosaka; M. Kohara; S. L. Divers; H. Matsubara; L. G. Moore; S. Adachi, REPRODUCTION, 139, 1, 71, 83, Jan. 2010
  English
• 紅藻(ツルシラモ)を用いた魚類循環飼育水の水質浄化の検討
  増田淳史; 山本大輔; 山羽悦郎; 井尻成保; 安井肇; 足立伸次, 水産増殖, 57, 4, 661, 20 Dec. 2009
  Japanese
• Eel and sturgeon, unmanageable species in seeding production
  Shigehiro Ijiri, NIPPON SUISAN GAKKAISHI, 75, 5, 866, 867, Sep. 2009, [Invited]
  Japanese, Introduction scientific journal
• In vitro induction of oil droplet accumulation into previtellogenic oocytes of Japanese eel, Anguilla japonica
  Taku Endo; Takashi Todo; P. Mark Lokman; Shigeho Ijiri; Shinji Adachi; Kohei Yamauchi, CYBIUM, 32, 2, 239, 240, Jul. 2008
  English
• Growth and differentiation factor-9 in the ovary of the eel (Anguilla SPP.)-stage dependence and hormonal control of expression-
  Lokman P M; Kazeto Y; Ijiri S; Tosaka R; Kohara M; Divers S L; Matsubara H; Adachi S, 6 th International Symposium on Fish endocrinology, Jun. 2008
  ウナギ卵巣に発現するGDF-9遺伝子を単離・発現変化を調べた。（Lokman P M, Kazeto Y, Ijiri S, Tosaka R, Kohara M, Divers S L, Matsubara H, Adachi S.）ポスター発表, English, Introduction international proceedings
• Immunohistochemical characterization of gonadal soma-derived growth factor (GSDF) in male undifferentiated gonad of the Nile tilapia.
  KURAMOCHI Yuki; IJIRI Shigeho; KANEKO Hiroyo; KANEKO Hiroyo; KOBAYASHI Tohru; NAGAHAMA Yoshitaka; NAGAHAMA Yoshitaka; ADACHI Shinji, Program & Abstracts. 5th World Fisheries Congress, 2008, 2008
• ニホンウナギのアロマターゼおよび3β-水酸基脱水素酵素の生殖腺における発現解析
  風藤行紀; 小原真由子; 武井則雄; 井尻成保; 足立伸次; 山内晧平, 日本水産学会大会講演要旨集, 2008, 2008
• 性分化期のティラピア生殖腺における性分化関連遺伝子の発現変化
  井尻成保; 金子裕代; 王徳寿; 足立伸次; 長濱嘉孝; 長濱嘉孝, 日本水産学会大会講演要旨集, 2007, 2007
• ニホンウナギの卵質評価マーカータンパクの検索
  佐合慶祐; 佐合洋祐; 小林亨; 長濱嘉孝; 小林弘子; 井尻成保; 足立伸次; 山内晧平, 日本水産学会大会講演要旨集, 2007, 2007
• GENE EXPRESSION PATTERN IN TILAPIA GONADS DURING SEX DIFFERENTIATION
  IJIRI Shigeho; KANEKO Hiroyo; WANG De-shou; ADACHI Shinji; NAGAHAMA Yoshitaka, Proceedings of the Japan Society for Comparative Endocrinology, 21, 47, 47, Nov. 2006
  English, Summary international conference
• Gene expression profile in Nile tilapia gonad during sex differentiation
  S Ijiri; D Wang; Y Nagahama, JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-COMPARATIVE EXPERIMENTAL BIOLOGY, 305A, 2, 135, 135, Feb. 2006
  English, Summary international conference
• ティラピア性分化期の生殖腺における性分化関連遺伝子の発現変化
  井尻成保; 金子裕代; 王徳寿; 足立伸次; 長濱嘉孝, 日本比較内分泌学会大会及びシンポジウムプログラム・講演要旨, 31st, 2006
• GENE EXPRESSION PATTERN IN TILAPIA GONADS DURING SEX DIFFERENTIATION
  IJIRI SHIGEHO; KANEKO HIROYO; WANG DE-SHOU; ADACHI SHINJI; NAGAHAMA YOSHITAKA, Proc Jpn Soc Comp Endocrinol, 21, 47, 2006
  English, Summary national conference
• 性分化期のティラピア生殖腺における発現遺伝子
  井尻成保; 王徳寿; 松田勝; 長浜嘉孝, 日本水産学会大会講演要旨集, 2005, 48, 01 Apr. 2005
  Japanese
• Induction of oogenesis by injections of salmon pituitary homogenates in hypophysectomized immature Japanese eel
  Matsubara H; Senaha A; Takei N; Shin D H; Ijiri S; Todo T; Adachi S; Yamauchi K, Zoological Science, 1603, 1603, Dec. 2003
  脳下垂体を摘除したニホンウナギ雌に人為催熟を施したところ卵成長が進行した。（Matsubara H, Senaha A, Takei N, Shin D H, Ijiri S, Todo T, Adachi S, Yamauchi K.）Zoological Science 2003; 20: p1603.ポスター発表, Japanese, Introduction international proceedings
• 魚類の卵形成におけるアンドロゲンの役割
  瀬名波絢子; 松原創; 井尻成保; 足立伸次; 山内晧平, 道立水産孵化場と北大水産学部の研究交流会 魚の研究 to be continued, Feb. 2003
  アンドロゲンがニホンウナギおよびベステルの卵形成に及ぼす影響を調べた。（瀬名波絢子、松原創、井尻成保、足立伸次、山内晧平.）ポスター発表, Japanese, Introduction other
• EFFECTS OF CORTISOL ADMINISTRATION ON SEX DETERMINATION, BODY COLOR AND GROWTH IN FISH(Endocrinology,Abstracts of papers presented at the 74^ Annual Meeting of the Zoological Society of Japan) :
  Takahashi Akari; Takahashi Takayuki; Ijiri Shigeho; Adachi Shinji; Yamauchi Kohei, Zoological science, 20, 12, 1603, 1603, 2003
  Zoological Society of Japan, English
• CHANGES IN IMMUNOLOCALIZATION OF STEROIDOGENIC ENZYMES (P450SCC, P450C17, P450AROM) IN GONAD OF THE JAPANESE EEL(Endocrinology,Abstracts of papers presented at the 74^ Annual Meeting of the Zoological Society of Japan) :
  Takei Norio; Ijiri Shigeho; Adachi Shinji; Yamauchi Kohei, Zoological science, 20, 12, 1603, 1603, 2003
  Zoological Society of Japan, English
• Synthesis and possible function of 11-ketotestosterone during oogenesis in eel (Anguilla spp.) (vol 28, pg 353, 2003)
  H Matsubara; PM Lokman; A Senaha; Y Kazeto; S Ijiri; A Kambegawa; T Hirai; G Young; T Todo; S Adachi; K Yamauchi, FISH PHYSIOLOGY AND BIOCHEMISTRY, 29, 3, 253, 253, 2003
  English, Others
• Oogenesis in the Japanese eel, Anguilla japonica
  S Adachi; S Ijiri; Y Kazeto; K Yamauchi, EEL BIOLOGY, 301, 317, 2003, [Invited]
  English
• The GnRH system in zebrafish (Danio rerio): Developing a model system for functional studies of GnRH multiplicity.
  KE Kight; Steven, SR; S Ijiri; D Alok; U Klenke; Y Zohar, BIOLOGY OF REPRODUCTION, 66, 299, 300, 2002
  English, Summary international conference
• Changes in steroidogenic enzyme mRNA levels in ovarian follicles of artificially maturing Japanese eel
  Matsubara H; Kazeto Y; Ijiri S; Abe T; Inaba K; Seki S; Hirai T; Adachi S; Yamauchi K, The 25th Symposium on the Japan Society for Comparative Endocrinology, Dec. 2000
  人為催熟に伴うニホンウナギ卵濾胞における5種のステロイド合成酵素遺伝子量を比較した。(Matsubara H, Kazeto Y, Ijiri S, Abe T, Inaba K, Seki S, Hirai T, Adachi S, Yamauchi K) The 25th Symposium on the Japan Society for Comparative Endocrinology. 2000 ; 15 : p10.ポスター発表, English, Introduction international proceedings
• 人為催熟および天然ウナギ卵巣のステロイド合成酵素発現量の比較
  松原創; 風藤行紀; Lokman P M; 奥村浩美; 井尻成保; 足立伸次; 山内晧平, 魚の研究 to be continued, Nov. 1998
  前卵黄形成期、卵黄形成初期および中期における人為催熟ニホンウナギと天然ニュージーランドロングフィンウナギ卵巣の３種のステロイド合成酵素遺伝子量を比較した。（松原創、風藤行紀、 Lokman P M、奥村浩美、井尻成保、足立伸次、山内晧平）ポスター発表, 道立水産孵化場と北大水産学部の研究交流会, Japanese, Introduction other
• MOLECULAR CLONING OF OVARIAN 17β-HYDROXYSTEROID DEHYDROGENASE AND CHANGES IN ITS EXPRESSION DURING SEXUAL MATURATION IN THE JAPANESE EEL
  MATSUBARA Hajime; KAZETO Yukinori; IJIRI Shigeho; ADACHI Shinji; YAMAUCHI Kohei, Proceedings of the Japan Society for Comparative Endocrinology, 13, 56, 56, Jul. 1998
  English
• Isolation and characterization of cytochrome P450 aromatase (CYP19) from a cartilaginous fish, the Atlantic stingray
  S Ijiri; JM Trant, FASEB JOURNAL, 12, 8, A1426, A1426, Apr. 1998
  English, Summary international conference
• MOLECULAR CLONING OF THE cDNA ENCODING P450 17α-HYDROXYLASE/C_<17-20>LYSE (P450c17) FROM THE JAPANESE EEL OVARY AND DEVELOPMENTAL CHANGES IN ITS EXPRESSION IN THE OVARY
  KAZETO Y.; IJIRI S.; ADCHI S.; YAMAUCHI K., Proceedings of the Japan Society for Comparative Endocrinology, 12, 44, 44, Jul. 1997
  English
• GONADOTROPIN INDUCES AN INCREASE IN 17α,20β-DP RECEPTOR CONCENTRATION AND THE DEVELOPMENT OF OOCYTE MATURATIONAL COMPETENCE IN A TELEOST, THE HIRAME, Paralichthys olivaceus.(Developmental Biology)Proceedings of the Sixty-Third Annual Meeting of the Zoologiacal Socistry of Japan :
  Yoshikuni M.; Nagahama Y.; Adachi S.; Ijiri S.; Yamauchi K., Zoological science, 9, 6, 1162, 1162, 1992
  Zoological Society of Japan, English

• Eel science
  塚本, 勝巳; 黒木, 真理; Watanabe; Soichi eds; Chapter; Reproduction, Shigeho Ijiri, Hajime Matsubara, Moemi Horiuchi, and Yukinori Kazeto., Chapter 12; Reproduction
  Springer, 2024, 9789819956913, viii, 318 p., English
• 魚類の性決定・性分化・性転換 : これまでとこれから = Sex determination, sex differentiation and sex change in fishes-past, present and future
  菊池, 潔; 井尻, 成保; 北野, 健; 日本水産学会, 第6章 ティラピア・チョウザメの性分化
  恒星社厚生閣, Mar. 2021, 9784769916635, xiv, 242p, Japanese, [Joint editor]
• ウナギの科学
  塚本, 勝巳
  朝倉書店, Jun. 2019, 9784254485028, x, 226p, 図版 [8] p, Japanese, [Contributor]
• 魚類学の百科事典
  井尻 成保, 生殖腺の性決定と性分化
  丸善, Oct. 2018, 9784621303177, Japanese, Dictionary or encycropedia, [Contributor]
• 海をまるごとサイエンス
  井尻 成保, 第4章殖えない魚を殖やしたい：難種苗生産魚種への挑戦
  Aug. 2018, 9784303800017, 127, 42-54, Japanese, General book, [Contributor]
• 魚類学
  井尻 成保, 第14章生殖
  恒星社厚生閣, Sep. 2017, 388, 155-178, Japanese, Scholarly book, [Contributor]
• Eel Biology
  Adachi S; Ijiri S; Kazeto Y; Yamauchi K, Oogenesis in the Japanese eel.
  Springer-Verlag, 2003, 4431004580, 497, 301-318, Japanese, Scholarly book, [Contributor]

• ティラピア、チョウザメ、ウナギの性分化
  井尻 成保
  平成30年度日本水産学会秋期大会、シンポジウム「魚類の性決定・性分化・性転換 –これまでとこれから–」, 18 Sep. 2018, Japanese, Nominated symposium
  [Domestic Conference]
• Molecular mechanism of maturation-inducing steroid synthesis during oocyte maturation
  IJIRI Shigeho
  International Fisheries Symposium, 02 Nov. 2016, English
  [International presentation]
• Molecular mechanism of maturation-inducing steroid synthesis during oocyte maturation in Japanese eel
  IJIRI Shigeho
  Towards reproduction of eel in captivity to support sustainable aquaculture, 20 Oct. 2016, English, Nominated symposium
  [Invited], [International presentation]
• Molecular mechanism of the maturation-inducing hormone production in cultured ovaries of the Japanese eel, Anguilla japonica
  IJIRI Shigeho
  International Symposium on Fish Endocrinology, 28 Jun. 2016, English, Invited oral presentation
  [Invited], [International presentation]
• 水産重要魚種、ウナギとチョウザメの増養殖研究におけるNGSの利用
  井尻 成保
  NGS現場の会 第四回研究会, 01 Jul. 2015, Japanese, Invited oral presentation
  [Invited], [Domestic Conference]
• ウナギ増養殖研究の最前線
  井尻 成保
  平成27年度資源・素材学会北海道支部春季講演会, 13 Jun. 2015, Japanese, Invited oral presentation
  [Invited], [Domestic Conference]
• Molecular mechanism of maturation-inducing hormone production during final oocyte maturation in the japanese eel.
  Ijiri, S; Su, T; Kato, R; Kazeto; Y. Kagawa, H; Adachi, S
  10th International Symposium on Reproductive Physiology of Fish., 25 May 2014, English, Invited oral presentation
  [Invited], [International presentation]
• Dimorphic expression pattern of sex differentiation-related genes in morphologically undifferentiated gonads of Amur sturgeon and Russian sturgeon
  Ijiri S; Hagihara Seishi; Yamashita R; Suzuki H; Adachi S
  Diversification in Inland Finfish Aquaculture II, 24 Sep. 2013, English, Invited oral presentation
  [Invited], [International presentation]
• Identification of a novel type of 20beta-hydroxysteroid dehydrogenase responsible for maturation-inducing hormone production during oocyte maturation in masu salmon
  Shigeho Ijiri; Yasushi Shibata; Nonoha Takezawa; Yukinori Kazeto; Naoki Takatsuka; Erika Kato; Yuichi Ozaki; Shinji Adachi; Kohei Yamauchi; Yoshitaka Nagahama
  17th International Congress of Comparative Endocrinology, 16 Jul. 2013, English, Oral presentation
  [International presentation]
• ニホンウナギ増殖研究の過去と現在
  井尻 成保
  日本機械学会北海道支部総会付帯特別講演会, 17 Mar. 2012, Japanese, Nominated symposium
  [Invited], [Domestic Conference]

• Introduction to Fisheries Sciences Ⅱ（水産科学汎論Ⅱ）, 2024年, 修士課程, 水産科学院
• 増殖生物学特論Ⅰ, 2024年, 修士課程, 水産科学院
• 増殖生物学特論Ⅱ, 2024年, 修士課程, 水産科学院
• 大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
• 持続的生物生産技術特論, 2024年, 修士課程, 国際食資源学院
• 水族生殖生物学, 2024年, 学士課程, 水産学部
• 細胞生物学, 2024年, 学士課程, 水産学部
• 水圏生物学実験, 2024年, 学士課程, 水産学部
• 環境と人間, 2024年, 学士課程, 全学教育
• 水産増養殖実習, 2024年, 学士課程, 水産学部
• 水産科学英語Ⅰ, 2024年, 学士課程, 水産学部
• 水産科学英語Ⅱ, 2024年, 学士課程, 水産学部

• JAPANESE SOCIETY FOR AQUACULTURE SCIENCE
• JAPAN SOCIETY FOR COMPARATIVE ENDOCRINOLOGY
• 日本水産学会

• 核内受容体PPARを標的とした新たな魚類の性統御法の開発
  科学研究費助成事業
  01 Apr. 2024 - 31 Mar. 2027
  北野 健; 山口 寿哉; 川村 亘; 井尻 成保
  日本学術振興会, 基盤研究(B), 熊本大学, 24K01853
• チョウザメ類の排卵卵を用いた高品質キャビアの開発
  研究助成金
  Oct. 2025 - Sep. 2026
  駿河谷 諒平; 足立 伸次; 井尻 成保
  公益財団法人戸部眞紀財団, 北海道大学, 25-JE-005
• Exploration of the follicle-stimulating hormone-releasing hormone in the hypothalamus
  Grants-in-Aid for Scientific Research
  01 Apr. 2023 - 31 Mar. 2026
  神田 真司; 大久保 範聡; 井尻 成保
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), The University of Tokyo, 23K26999
• Exploration of the follicle-stimulating hormone-releasing hormone in the hypothalamus
  Grants-in-Aid for Scientific Research
  01 Apr. 2023 - 31 Mar. 2026
  神田 真司; 大久保 範聡; 井尻 成保
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), The University of Tokyo, 23H02306
• Studies on regulatory mechanisms underlying steroidogenic enzyme expression that governs sex differentiation, oocyte growth and maturation in teleost
  Grants-in-Aid for Scientific Research
  01 Apr. 2022 - 31 Mar. 2026
  井尻 成保; 木村 敦
  本研究は、条鰭類全体の卵巣分化・発達を通したステロイドホルモン合成系の変化を、その代謝酵素の転写調節の面から明らかにする。卵黄形成時にはエストロゲンであるE2が、卵成熟時には卵成熟誘起ステロイドであるDHPが主に産生され、このE2からDHPへの産生転換は劇的に生じる。本研究ではその転写調節をFSHとLHの作用に焦点を当てて調べる。
  E2産生を制御する律速酵素、アロマターゼをコードするcyp19a1遺伝子については、ティラピア、ウナギともにfoxl2、sf1の存在下でFSH刺激により最も高い転写活性が誘導されることが示された。ウナギについては、foxl2の働きを抑制する機構の存在が示唆された。
  DHP産生の律速酵素である20β-HSDをコードするhsd17b12L遺伝子について、ウナギではこの遺伝子発現変化がDHP産生の調節要因ではないと結論された。チョウザメ、サクラマスではLHによる転写活性化は直接的ではなかったことから、他の因子の介在が考えられた。hsd17b12Lの転写を誘導する因子についてはサクラマスにおいて探索している。
  ウナギではhsd17b12Lの転写活性化がDHP産生の制御要因ではないことから、その前駆体である17OHP産生機構に焦点を当てて調べ、プロゲステロンをアンドロステンジオンに代謝するcyp17a1の発現消失によって17OHPが産生されるということを強く示唆している。Cyp17a1遺伝子の発現を抑制する因子の存在が考えられ、その因子の同定を進めている。
  以上の結果は、ステロイド代謝酵素はLH、FSHによる単純な発現調節ではなく、様々な転写因子が関わる複雑な調節機構であり、それぞれの酵素にそれぞれ異なった転写調節因子が関わっていることを示している。その機構はcyp19を除いてほとんど解っておらず、これを解明する意義は大きい。
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23K23696
• Studies on regulatory mechanisms underlying steroidogenic enzymes expression that governs sex differentiation, oocyte growth and maturation in teleost
  Grants-in-Aid for Scientific Research
  01 Apr. 2022 - 31 Mar. 2026
  井尻 成保; 木村 敦
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 22H02431
• Molecular studies on sex differentiation, oocyte maturation, ovulation, and egg quality loss in sturgeons
  Grants-in-Aid for Scientific Research
  01 Apr. 2021 - 31 Mar. 2025
  足立 伸次; 井尻 成保
  １）性分化：昨年度は、雌特異的ゲノム領域上に存在する遺伝子のうち、未分化生殖腺で発現する遺伝子Xを特定し、本遺伝子内配列および雄特異的プライマーを用いることで、調べたすべてのチョウザメ種で偽雄や超雌を識別した。本年度は、遺伝子Xおよび性分化関連遺伝子の発現変化を調べ、性的二型発現を示す遺伝子を複数明らかにすることができた。これら遺伝子の生体外培養による発現制御解析を試みたが、稚魚の生残が悪く、十分な未分化生殖腺を採取できなかった。しかし、培養に用いる組換え生殖腺体細胞由来増殖因子(Gsdf)を作製するための2種のgsdfの全長ORFを単離できた。
  ２）卵成熟・排卵：チョウザメの場合、生体外培養で卵成熟能および排卵能を確認した後、生殖腺刺激ホルモン放出ホルモン（GnRH）注射で卵を得ているが、タイミングが不適切な場合は良質卵は得られない。しかし、排卵能確認には数日要する。排卵能獲得前後に発現消長する排卵誘導マーカーを指標とした推定法を確立できれば、短時間で採卵適期の推定可能となる。本年度は、アムールチョウザメの排卵誘導マーカーsfrp2（Wntインヒビター）について発現動態を調べた結果、GnRH注射前では高発現であったが、GnRH注射によりほぼ消失した。
  ３）卵質悪化：これまで、ニホンウナギにおいて、母性mRNA量および局在の差異から、孵化までの胚発生異常が生じる不良卵の分子生物学的特徴の一部を明らかにしている。本年度は、これまで得てきたアムールチョウザメ卵の中で、比較的卵質が良いと思われるサンプルをNGSに供し、ESTdbを構築した。また、in situ hybridizationにより、卵母細胞の発達に伴うsybu（母性mRNAのひとつ）の発現局在を調べた。その結果、周辺仁期から油球形成後期において、油球形成の進行に伴い細胞質全体から周縁部に局在が変化することを明らかにした。
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23K21228
• Molecular studies on sex differentiation, oocyte maturation, ovulation, and egg quality loss in sturgeons
  Grants-in-Aid for Scientific Research
  01 Apr. 2021 - 31 Mar. 2025
  足立 伸次; 井尻 成保
  本研究では、チョウザメの性分化、卵成熟、排卵および卵質悪化の分子機構解明を推進し、各ステージに特徴的な分子マーカーを利用して、早期性判別、安定的良質卵生産技術および全雌生産技術を確立することを目的としており、本年度は下記の3項目について、分子機構解析と関連技術開発を行なった。
  １）性分化：最近、コチョウザメにおいて雌特異的な増幅を示すプライマー（AllWSex2）が見出された。本年度は、アムール、ダウリア（カルーガ）、ミカドチョウザメおよび各種雑種において、本プライマーを用いた遺伝的性判別が可能であることを検証できた。さらに、チョウザメ類における濾胞刺激ホルモン（Fsh）と性分化との関係を明らかにするために、組換えFshを作製し、レポーターアッセイにより生物活性を有することを確認した。
  ２）卵成熟および排卵：チョウザメの場合、生体外培養で卵成熟能および排卵能を確認した後、生殖腺刺激ホルモン放出ホルモン（GnRH）注射することで卵を得ているが、タイミングが不適切な場合は良質卵が得られない。これまで、プロスタグランジン合成関連遺伝子発現を指標とした採卵適期推定法を検討してきたが、適当な指標はみつからなかった。そこで、GnRH注射の直前に採取したアムールチョウザメ卵濾胞サンプルを用いて、RNA-seq解析を行なったところ、いくつかの候補遺伝子を見出した。これら遺伝子のうち、Wntシグナルに関与する2個の遺伝子の発現動態を調べたところ、排卵個体ではGnRH注射直前に発現ピークが存在することが判明した。
  ３）卵質悪化：これまで、ニホンウナギにおいて、母性mRNA量および局在の差異から、孵化までの胚発生過程で異常が生じる不良卵の分子生物学的特徴の一部を明らかにしている。本年度は、様々な卵質のアムールチョウザメ卵を得ることができた。
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 21H02264
• 条鰭類を網羅する卵成熟誘起ホルモン産生分子機構の解明
  科学研究費補助金 基盤研究（B)
  Apr. 2018 - Mar. 2022
  井尻成保
  日本学術振興会, Principal investigator, Competitive research funding
• ウナギ雌化と食味に優れた大型雌ウナギの生産技術の確立
  イノベーション創出強化研究推進事業
  Apr. 2018 - Mar. 2021
  稲葉博之
  農研機構, Competitive research funding
• チョウザメの性分化および卵成熟／排卵の分子機構に関する研究
  科学研究費補助金 基盤研究（B)
  Apr. 2017 - Mar. 2021
  足立伸次
  日本学術振興会, Competitive research funding
• 環境依存的性決定の分子機構とその普遍性の解析
  科学研究費補助金 基盤研究（B)
  Apr. 2016 - Mar. 2019
  北野健
  日本学術振興会, Competitive research funding
• バキュロウイルス遺伝子導入系の魚類生殖生理研究における利用技術開発
  科学研究費補助金 挑戦的萌芽研究
  Apr. 2016 - Mar. 2019
  井尻成保
  日本学術振興会, Principal investigator, Competitive research funding
• Generation of transgenic Medaka producing a transporter targeting to fish oocytes
  Grants-in-Aid for Scientific Research
  01 Apr. 2015 - 31 Mar. 2018
  HIRAMATSU Naoshi; IJIRI Shigeho; KAWAKAMI Koichi
  The aim of this study is to obtain the first technical basis for the development of a bio-reactor system through the production of model transporters in transgenic fish, with the final goal of which constructs a system transporting various effective materials across generations (i.e., from mother to egg or larva) in fish. Various expression constructs were generated by combining transporters, fluorescent proteins, a linker, trans-genic vector systems. Trans-genic medaka expressing fluorescent model transporters, as well as a model transporter with a linker, were produced as the second (F1) and the third (F2, the fluorescent transporter alone) trans-genic generations. This study provided fundamental knowledge for the next examination toward a massive bio-production of the transporters.
  Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 15K14797
• ティラピア生殖腺の性分化開始機構の解明とその応用
  科学研究費補助金 基盤研究（B)
  Apr. 2014 - Mar. 2018
  井尻成保
  日本学術振興会, Principal investigator, Competitive research funding
• Sea urchin has steroid hormone metabolism ?
  Grants-in-Aid for Scientific Research
  01 Apr. 2013 - 31 Mar. 2016
  Ura Kazuhiro; TAKAGI Yasuaki; IJIRI Shigeho
  It is still unclear that the endocrine system such as synthesize and/or embolism of steroid hormones during the period of gonadal growth in sea urchin. This study aimed to identify genes involved in gonadal growth and to investigate gene expression in the period of gonadal growth in sea urchin. RNA-seq analysis using next-generation sequencer was carried out on growing gonads of the Northern sea urchin, Mesocentrotus nudus. BLASTn analysis identified 22 transcripts potentially involved endocrine factors such as nuclear receptor (NR) and 21 transcripts of P450 in the growing gonad. However, the homologous genes as ER, AR, P450scc, P450c17, P450arom were not observed in sea urchin. In these analysis, it is suggested that sea urchin has no sex steroid hormones as same as vertebrate. These results suggested that sea urchin synthesized steroid hormones as same as other insects.
  Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 25660159
• チョウザメの生殖統御技術開発のための性分化、卵成長および卵成熟の分子機構解析
  科学研究費補助金 基盤研究（A）
  Apr. 2012 - Mar. 2016
  足立伸次
  日本学術振興会, Competitive research funding
• 魚類最終成熟誘起ステロイド産生メカニズムの定説を覆す
  科学研究費補助金 挑戦的萌芽研究
  Apr. 2012 - Mar. 2014
  足立伸次
  日本学術振興会, Competitive research funding
• 超雄・超雌作製と早期性判別を実現するための性連鎖DNA配列段階的同定法の確立
  科学研究費補助金 挑戦的萌芽研究
  Apr. 2011 - Mar. 2014
  井尻成保
  日本学術振興会, Principal investigator, Competitive research funding
• 最新の生理生態情報に基づくウナギ大量種苗生産技術の実現
  科学研究費補助金 基盤研究（S）
  2008 - 2014
  塚本勝巳
  日本学術振興会, Competitive research funding
• 魚類養殖及び放流事業の性統御を可能にする遺伝的雌雄判別技術の開発
  地域イノベーション創出総合支援事業「シーズ発掘試験」
  Apr. 2009 - Mar. 2010
  井尻成保
  科学術振興機構, Principal investigator, Competitive research funding
• Mechanism of previtellogenic oocyte growth in fish
  Grants-in-Aid for Scientific Research
  2007 - 2009
  ADACHI Shinji; IJIRI Shigeho; TODO Takashi
  Estrogen treatment may promote oocyte growth during ovarian differentiation in eel and sturgeon. Androgen treatment accelerates previtellogenic oocyte growth in eel. Somatic growth may promote oocyte growth between estrogen and androgen-dependent phase in fish.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 19380107
• ティラピアの生殖腺の性分化に関わる遺伝子の特定と機能解析
  科学研究費補助金 若手研究B
  Apr. 2006 - Mar. 2008
  井尻成保
  日本学術振興会, Principal investigator, Competitive research funding
• 催熟ウナギ雌の脳下垂体の成熟への関与に関する内分泌学的研究
  科学研究費助成事業
  2001 - 2003
  井尻 成保
  昨年度までの脳下垂体除去雌ウナギの催熟実験によって、通常のウナギ人為催熟には、ウナギ自身の脳下垂体は必ずしも必要ではないことがあきらかとなった。本年度は、主要なステロイド合成酵素の抗体を作製し、タンパクレベルでの発現制御の解明、および未だ単離されていないステロイド合成酵素の単離を目指した。1)20β-HSD遺伝子の単離:他魚種で20β-HSDとして単離されているカルボニル還元化酵素はウナギでは20β-HSD活性を持たなかったことから他のタイプが存在すると仮定して、機能発現クローニングを試みたが20β-HSD活性を持つ遺伝子を単離するには至らなかった。2)P450c11の免疫組織化学的局在:ウナギP450c11組替タンパクに対する特異抗体を作製し、ウナギ組織を免疫染色した結果、頭腎のステロイド合成細胞および精巣のライディッヒ細胞が良好に染色されたが、卵巣に陽性細胞は観察されなかった。この時期卵巣のP450c11 RNAの発現は高い為、矛盾する結果となった。3)P450scc、P450c17、P450c11のmRNAの局在:卵巣ではscc、c17ともにmRNAはタンパクと同時期、同部位に発現していた。精巣では催熟開始直後に発現が高まるも、以降ほとんど発現は認められず、scc、c17ともタンパクが一貫して発現している様子とは異なった。精巣のc11に関しては催熟開始9日目にmRNA、タンパクともにほぼ同時期に発現していた。以上、これまでにニホンウナギのFSH、サケFSH、P450scc、P450c17、P450arom、P450c11の特異抗体を作製し、免疫組織化学的観察を行った。これまでの結果、ウナギ雌の人為催熟にはウナギ自身の脳下垂体は必ずしも必要でなく、つまり様々なステロイド合成酵素は注射されるサケ下垂体によって発現が促進されている者と考えられた。そのステロイド合成酵素の発現制御も各々異なるとが示唆された。
  日本学術振興会, 特別研究員奨励費, 北海道大学, 01J10618