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Annual changes of the gonad and reproductive endocrinology in hynobiid salamanders

小鲵性腺和生殖内分泌的年度变化

基本信息

批准号：
04640687
负责人：
IWASAWA Hisaaki
金额：
$ 1.09万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Annual changes of reproductive organs were histologically studied in two species of hynobiid salamanders, Hynobius nigrescens and H.retardatus. The most conspicuous difference found between the two species was the duration of inactive period of spermatogenesis after the breeding season. Inactive duration was 4 months in the former, and 0 month in the latter. Furthermore, the fat body developed very rapidly after the breeding period in H.retardatus. This diffrence is closely related to the length of hibernating period. The hibernating period is 4 months in H.nigrescens, and 7 months in H.retardatus. Concerning the plasma concentrations of sex steroids in H.nigrescens, the concentration of progesterone was strikingly high at the time of ovulation, and the concentration of estradiol was highest in autumn in females. In males the concentration of testosterone was remarkably high at the time of spermiation. Annual changes in the functional activity of gonadotropin-producing cells were immunocytochemically studied in H.nigrescens. The results obtained well coincided with the changes in the gonadal histology and the plasma concentration of sex steroids. In sexually active males found in the breeding pond, the anterior lobe of the pituitary was remarkably large in size. The youngest age of sexual maturation in H.nigrescens was various according to habitat, and 3 years old in a hillside and 5 in a mountain district. The longest life span was 14 years old as far as we observed.

用组织学方法研究了两种蝾螈生殖器官的年变化。两种间最显著的差异是繁殖季节后精子发生不活跃期的持续时间。前者失活时间为4个月，后者为0个月。此外，在繁殖期后，滞发绦虫的脂肪体发育非常迅速。这种差异与冬眠时间的长短密切相关。黑僵螨的冬眠期为4个月，迟滞螨的冬眠期为7个月。在性甾体激素的血浆浓度方面，雌性在排卵期黄体酮浓度显著高，雌二醇浓度在秋季最高。在雄性中，睾酮浓度在精子受精时非常高。用免疫细胞化学方法研究了促性腺激素产生细胞的功能活性的年变化。所得结果与性腺组织学和血浆性类固醇浓度的变化吻合较好。在繁殖池中发现的性活跃的雄性，垂体前叶的大小非常大。不同生境的黑毛猴性成熟年龄不同，山坡性成熟年龄为3岁，山地性成熟年龄为5岁。据我们观察，最长的寿命是14岁。