| Project/Area Number |
63560253
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
畜産学(含草地学)
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
UMEZU Motoaki Tohoku Univ. Fac.Agric., Res.Associate, 農学部, 助手 (30005649)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1989: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | sexual maturation / rat / hormone / FSH / inhibin / lighting cycle / testosterone / vaginal opening / 雄ラット / テストテロン / 潜伏精巣 / 雌ラット / 照明条件 / 初回排卵 / 生殖ホルモン |
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| Research Abstract |
Annual season affects sexual manifestations in mammals. Also in rat, onset of puberty is known to be affected by daily lighting. But the details of the condition on reproductive endocrine system in the rats are not clarified. In 1088, female rats were fed from birth to puberty under the condition of complete lighting(LL) or darkness(DD) and observed if vaginal opening as an index of puberty was advanced or delayed compared the those fed with normal lighting. Elevated levels of serum FSH in the infantile, subsequent follicular development in the early juvenile leading to puberty advanced or delayed in LL or DD rats. It is concluded that the elevated FSH levels in the infantile is a key phenomenon to subsequent puberty.
In 1989, puberty indexed with elevated secretion of testosterone(T) was examined with reference to the development of reproductive endocrine system until puberty in normal lighting condition. Weight of testis increased linearly with age but weight of seminal vesicles increased rapidly during 45-50 days of age, when T in blood and testis increased correspondingly. FSH levels increased from 10-30 days and the levels were maintained from 30 to 40 days. These levels dropped suddenly at 40-43 days followed by the elevation again. The sudden decrease of FSH corresponded with increase of testicular inhibin. The period preceded to the activated secretion of T. LH levels were not hightened with the T secretion suggesting that responsibility of testis to LH changed prior to puberty.
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