Sarkar S, Sarkar N K, Das P, Maiti B R
Department of Zoology, University of Calcutta, India.
J Exp Zool. 1996 Jan 1;274(1):41-55. doi: 10.1002/(SICI)1097-010X(19960101)274:1<41::AID-JEZ5>3.0.CO;2-F.
Investigations were carried out to find out the role of higher and lower ambient temperatures together with short and long photoperiods on ovarian growth and secretion of steroids (estradiol-17 beta and progesterone) in the adult female soft-shelled turtle Lissemys punctata punctata during the preparatory, recrudescent, and quiescent phases of its seasonal reproductive cycle. In each phase, females were treated with 3 degrees C higher and 3 degrees C lower than the mean highest and lowest ambient temperatures in association with short and long photoperiods for short-term (4 week) and long-term (8 weeks or more) durations. Short-term high-temperature treatment significantly stimulated ovarian growth and secretion of estradiol-17 beta during the preparatory phase. Eight-week treatment failed to exercise further stimulation over 4-week treatment, whereas 10-week treatment caused regressive changes of ovary (atresia of follicles). Both short- and long-term high-temperature treatments caused degeneration of ovarian follicles during the recrudescent phase. Low-temperature treatment slowed down ovarian growth and secretion in both the preparatory and recrudescent phases. In the quiescent phase, low- as well as high-temperature treatments exercised little influence over the refractory ovarian growth and secretion. Photoperiod appeared to have no effect on female reproduction in any phase. Thus, high temperature is suggested to have a triggering role on ovarian growth and secretion of estrogen at the early preparatory phase, but once the ovarian function sets in, high temperature seems to have a regressive rather than stimulatory effect on ovarian growth and function.
进行了调查，以研究在成年雌性印度鳖季节性繁殖周期的准备期、复发期和静止期，较高和较低的环境温度以及短和长光照周期对卵巢生长和类固醇（雌二醇 - 17β和孕酮）分泌的作用。在每个阶段，将雌性分别置于比平均最高和最低环境温度高3摄氏度和低3摄氏度的环境中，并结合短光照周期和长光照周期，处理短期（4周）和长期（8周或更长时间）。短期高温处理在准备期显著刺激了卵巢生长和雌二醇 - 17β的分泌。8周处理相对于4周处理未能进一步刺激，而10周处理导致卵巢出现退行性变化（卵泡闭锁）。短期和长期高温处理在复发期均导致卵巢卵泡退化。低温处理在准备期和复发期均减缓了卵巢生长和分泌。在静止期，低温和高温处理对难治性卵巢生长和分泌影响很小。光照周期在任何阶段似乎对雌性繁殖均无影响。因此，高温在准备期早期对卵巢生长和雌激素分泌具有触发作用，但一旦卵巢功能开始，高温似乎对卵巢生长和功能具有退行性而非刺激性作用。
