| Project/Area Number |
62480022
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
動物形態・分類学
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
HIRANO Tetsuya OCEAN RES. INST., UNIV. TOKYO PROFESSOR, 海洋研究所, 教授 (70013571)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IWATA Munehico OCEAN RES. INST., UNIV. TOKYO ASSIST. PROFESSOR, 海洋研究所大槌臨界センター, 助手 (20090475)
KAWAUCHI Hiroshi SCH. FISH., KITASATO UNIV. PROFESSOR, 水産学部, 教授 (70050523)
小笠原 強 東京大学, 海洋研究所, 助手 (20167315)
|
|---|
| Project Period (FY) |
1987 – 1989
|
| Project Status |
Completed (Fiscal Year 1989)
|
| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1988: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1987: ¥3,000,000 (Direct Cost: ¥3,000,000)
|
|---|
| Keywords | Salmon / Trout / Thyroid Gland / Thyroid Hormones / Thyroxine / Triiodothyronine / Migration / Early Development / ビワマス / ヒラメ / コルチソル / 甲状腺刺激ホルモン |
|---|
| Research Abstract |
Thyroid hormones have been implicated in migration of salmonids, particularly in their downstream migration associated with smoltification. In this study, a method has been established to extract thyroid hormones, thyroxine and triiodothyronine, from the.egg and whole embryo and to quantify by radioimmunoassays. Thyroid hormones were contained in the yolk of unfertilized eggs of not only salmonids but also of all teleost species so far examined. In chum salmon and rainbow trout, the hormone concentrations decreased gradually until hatching, and then rapidly during yolk absorption.
The tissue and plasma levels of the hormones increased during emergence of chum salmon fry from the gravel bed, just before downstream migration.
No such increase was seen in non-migratory rainbow trout. A significant increase in the plasma levels of thyroxine was observed in the chum salmon fry as well as in amago salmon during downstream migration. A marked increase in the tissue levels of the thyroid hormones was also observed during metamorphic climax of the flounder larvae. Corticosteroid, cortisol, was also contained ih the salmon eggs, and changes in its concentrations were more or less in parallel with those in the thyroid hormones. The hormones seem to play important roles during early development of fishes, especially in association with migration and metamorphosis.
|
