Weber A L, Adler N T
Science. 1979 Apr 20;204(4390):323-5. doi: 10.1126/science.571146.
The normal ovarian cycle of female rats is typically replaced by persistent estrus when these animals are housed under constant light. Evidence presented here shows that the maintenance of periodicity in the environment can at least delay (if not prevent) the photic induction of persistent vaginal estrus. Female rats in constant light were exposed to vaginal smearing at random times or at the same time every day. In another experiment, female rats were exposed to either constant bright light, constant dim light, or a 24-hour photic cycle of bright and dim light. The onset of persistent vaginal estrus was delayed in rats exposed to 24-hour time cues even though the light intensities were the same as or greater than those for the aperiodic control groups. The results suggest that the absence of 24-hour time cues in constant light contributes to the induction of persistent estrus.
当雌性大鼠饲养在持续光照环境下时，其正常的卵巢周期通常会被持续性发情所取代。此处提供的证据表明，环境中周期性的维持至少可以延迟（如果不能预防的话）光照诱导的持续性阴道发情。持续光照下的雌性大鼠在随机时间或每天同一时间进行阴道涂片检查。在另一项实验中，雌性大鼠分别暴露于持续强光、持续弱光或强光与弱光交替的24小时光照周期下。暴露于24小时时间线索下的大鼠，即使光照强度与非周期性对照组相同或更高，其持续性阴道发情的 onset 也被延迟。结果表明，持续光照下缺乏24小时时间线索有助于诱导持续性发情。
原文中“onset”未翻译准确，可根据上下文进一步准确理解其含义后进行完善。
