2001 Fiscal Year Final Research Report Summary
MOLECULAR ENDOCRINOLOGICAL STUDY ON MECHANISMS OF ARTIFICIAL MATURATION IN FEMALE JAPANESE EEL
| Project/Area Number |
11460084
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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 | 一般 |
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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 Univ., Grad. School of Fish. Sci., Pro., 大学院・水産科学研究所, 教授 (10109514)
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| Co-Investigator(Kenkyū-buntansha) |
ADACHI Shinji Hokkaido Univ., Grad. School of Fish. Sci., Asso. Pro., 大学院・水産科学研究所, 助教授 (40231930)
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| Project Period (FY) |
1999 – 2001
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| Keywords | JAPANESE EEL / PITUITARY / LIVER / OVARY / VITLLOGENIN / NATURAL EEL / GTH / STEROID HORMONE |
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| Research Abstract |
1) Mechanism of pituitary GTH production
Changes in mRNA levels of GTH Iβ and IIβ subunits in pituitary of Japanese eel were examined during artificial maturation. The level of Iβ dramatically decreased immediately after the start of the treatment of artificial maturation, while the level of IIβdramatically increased. Experiment of pituitary organ culture revealed that estrogen and androgen strongly supressed the expression of Iβ, while they stimulated the expression of IIβ.
2) Mechanism of ovarian sterod production
cDNAs of P450scc, P450c17, P450arom, 3β-HSD and 17β-HSD were cloned from Japanese eel ovary. The mRNA levels of ovarian P450scc, P450c17 , P450arom and 17β-HSD gradually increased during artificial maturation although the level of P450arom decreased in final maturation phase, while the level of 3β-HSD did not change.
3) Mechanism of liver vitellogenin(VTG) production
The mRNA levels of VTG1 in liver increased after mid-vitellogenic stage, while the level of VTG2 increased immediately after the start of the treatment of artificial maturation.
4) Mechanism of sexual maturation in natural eel
The mRNA levels of GTH Iβ and IIβ in pituitary and various steroidogenic enzymes in ovary were compared between the artificially maturing Japanese eel (JP) and naturally maturing New Zealand longfinned eel (LF). The level of Iβ in LF was higher than that in JP. However, the levels of others were higher in JP than those in LF.
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