LONG-TERM REPRODUCTIVE EFFECTS OF A SINGLE LONG-DAY IN THE SIBERIAN HAMSTER (PHODOPUS-SUNGORUS)
LONG-TERM REPRODUCTIVE EFFECTS OF A SINGLE LONG-DAY IN THE SIBERIAN HAMSTER (PHODOPUS-SUNGORUS)
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DOI：
10.1177/074873049501000103
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发表时间：
1995-03-01
影响因子：
3.5
通讯作者：
ZUCKER, I
中科院分区：
文献类型：
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作者：
FINLEY, CM;GORMAN, MR;ZUCKER, I
西伯利亚仓鼠在18日龄时暴露于16小时间歇期的1- 4小时延长期，随后维持在短光周期（8L：16 D）中，直至第35天，睾丸退化被预防或减弱。睾丸重量在第35天没有相关的持续时间的活跃阶段的车轮运行或活动开始后转移到8L：16 D光周期的时间。轮运行活动不稳定夹带到35日龄的光暗周期。单个33小时光脉冲的促性腺作用在18日龄时最大，在30日龄时仍然明显，但在老年仓鼠中检测不到。在雌性仓鼠中，断奶时一天的延长与几周后的繁殖力增加有关。长时间的光周期加速了窦卵泡的发育，但在60日龄之前暴露于雄性是诱导排卵所必需的。断奶后不久开始的时间间隔是一个高度的反应，在白天长度（DL）的变化，暴露于增加DL在这个时候可能会延长繁殖季节时，DL夏至后下降。我们认为，急性光治疗对生殖的长期影响介导的持续变化，褪黑激素分泌诱导的昼夜节律振荡器的重新编程。
Testicular regression was prevented or attenuated in Siberian hamsters exposed to a single 1- to 4-h extension of the 16-h photophase at 18 days of age and subsequently maintained in a short photoperiod (8L:16D) through Day 35. Testicular weights on Day 35 were not correlated-with the duration of the active phase of wheel running or with the time of activity onset after transfer to the 8L:16D photoperiod. Wheel-running activity was not stably entrained to the light-dark cycle by 35 days of age. Progonadal effects of a single 33-h Light pulse were greatest at 18 days of age, still evident at 30 days, but undetectable in older hamsters. In female hamsters, a single longer day at weaning was associated with increased fecundity several weeks later. Long photoperiods accelerated development of antral ovarian follicles, but exposure to males was necessary to induce ovulation before 60 days of age. The interval beginning shortly after weaning is one of heightened responsiveness to changes in day length (DL); exposure to increasing DL at this time may prolong the breeding season when DL decreases after the summer solstice. We suggest that the long-term effects of acute Light treatments on reproduction are mediated by sustained changes in melatonin secretion induced by reprogramming of circadian oscillators.