2010 Fiscal Year Final Research Report
Elucidation of reproductive endocrine system in hagfish
| Project/Area Number |
20570054
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Morphology/Structure
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| Research Institution | Niigata University |
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Principal Investigator |
NOZAKI Masumi Niigata University, 自然科学系, 教授 (70136232)
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| Co-Investigator(Kenkyū-buntansha) |
UCHIDA Katsuhisa 宮崎大学, 農学部, 准教授 (50360508)
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| Project Period (FY) |
2008 – 2010
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| Keywords | 比較内分泌 |
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| Research Abstract |
Hagfishes, which lack both jaws and vertebrae, are considered the most primitive vertebrate known, living or extinct. Hagfishes have long been the enigma of vertebrate evolution not only due to their evolutionary position but also due to our lack of knowledge on fundamental processes. Key elements of the reproductive endocrine system in hagfish have yet to be elucidated. Here we report the first identification of a gonadotropic hormone (GTH) from the pituitary of the hagfish Paramyxine atami. The hagfish GTH consists of two subunits, α and β, which are synthesized and colocalized in the same cells of the adenohypophysis. The cellular and transcriptional activities of hagfish GTHα and β were significantly correlated with the developmental stages of the gonad. The purified native GTH induced the release of gonadal sex steroids in vitro. From our phylogenetic analysis, we propose that ancestral thyrostimulin alpha subunit and beta subunit gave rise to GTHα and GTHβ of the vertebrate glycoprotein hormone family, respectively. We hypothesize that the identity of a single functional GTH of the hagfish provides critical evidence for the existence of a pituitary-gonadal system in the earliest divergent vertebrate that likely evolved from an ancestral, pre-vertebrate exclusively neuroendocrine mechanism by gradual emergence of a new control level, the pituitary, that is not found in the Protochordates.
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[Journal Article] Evolutionary origin of a functional gonadotropin in the pituitary of the most primitive vertebrate, hagfish.2010
Author(s)
Uchida K., Moriyama, S., Chiba, H., Shimotani, T., Honda, K., Miki, M., Takahashi, A., Sower, S.A., Nozaki M.
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Journal Title
Proc.Natl.Acad.Sci.USA 107
Pages: 15832-15837
Peer Reviewed
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[Journal Article] Identity and distribution of immunoreactive adenohypophysial cells in the pituitary during the life cycle of sea lampreys, petromyzon marinus.2008
Author(s)
Nozaki M., Ominato, K., Shimotani, T., Kawauchi, H., Youson, J.H., Sower, S.A.
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Journal Title
Gen.Comp.Endocrinol. 155
Pages: 403-412
Peer Reviewed
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[Journal Article] Gene structure and functional characterization of growth hormone in dogfish, Squalus acanthias.2008
Author(s)
Moriyama, S., Oda, M., Tamazaki T., Yamaguchi K., Amiya, N., Takahashi, A., Amano, M., Goto, T., Nozaki M., Meguro, H., kawauchi, H.
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Journal Title
Zoological Science 25
Pages: 604-613
Peer Reviewed
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[Journal Article] cDNA cloning and isolation of somatolactin in Mozambique tilapia and effects of seawater acclimation, confinement stress, and fasting on its pituitary expression.2008
Author(s)
Uchida K., Moriyama, S., Breves, J.P., Fox, B.K., Pierce, A.L., Borski, R.J., Hirano, T., Gordon Grau, E.
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Journal Title
Gen.Comp.Endocrinol. 155
Pages: 403-412
Peer Reviewed
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