2003 Fiscal Year Final Research Report Summary
Establishment of methods for production of fish sperm in vitro
| Project/Area Number |
12556030
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
General fisheries
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| Research Institution | Hokkaido University |
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Principal Investigator |
YAMAUCHI Kohei Hokkaido University, Grad.School of Fish.Sci., Prof., 大学院・水産科学研究科, 教授 (10109514)
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| Co-Investigator(Kenkyū-buntansha) |
MIURA Takeshi Ehime University, Fac.of Agr., Prof., 農学部, 教授 (00261339)
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| Project Period (FY) |
2000 – 2003
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| Keywords | Spermatogenesis / Organ culture / Cell culture / Japanese eel / Growth factor / Steroid hormone / Gonadotropin / Spermiogenesis |
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| Research Abstract |
Considering the proliferation of bioresources, it is very important to understand the control mechanisms of gametogenesis (spermatogenesis and oogenesis) and regulate them artificially. In Japanese eel, complete spermatogenesis has been induced in vitro using an organ culture system and a germ-somatic cells coculture system. Thus, Japanese eel has been a good model for analysis of spermatogenesis. In this study, we investigated the molecular regulatory mechanisms of eel spermatogenesis, and tried to develop the culture systems to produce massive amounts of functional sperm in vitro.
We newly identified two important regulatory factors of spermatogenesis from Japanese eel, one is spermatogenesis-preventing substance, and another is spermatogonial stem cell renewal factor. The spermatogenesis-preventing substance is an eel homologue of Mullerian-inhibiting substance, and prevents the initiation of spermatogenesis (spermatogonial proliferation). The spermatogonial stem cell renewal factor is an eel homologue of platelet-derived endothelial growth factor, and induces the mitosis of spermatogonial stem cells. In addition, we suggested the presence of the meiosis-inducing hormone. To our knowledge, it is the first time to identify these spermatogenesis related factors. We established the method for transfer of foreign genes into testicular cells by electropolation. Furthermore, we found that the 3-D contact between germ and Sertoli cells is essential for induction of spermatogenesis in vitro. However, it has been failed to produce "functional" sperm in vitro. Further studies are needed to establish the complete system of in vitro sperm production.
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