Viswanathan N, Davis F C
Department of Biology, Northeastern University, Boston, Massachusetts 02115.
Biol Reprod. 1992 Jul;47(1):6-10. doi: 10.1095/biolreprod47.1.6.
The effects of mating time and of LD cycles on the timing of birth and length of gestation were examined in Syrian hamsters (Mesocricetus auratus). Hamsters maintained on 14L:10D cycles were mated for 2 h either in the evening or in the morning, and groups of hamsters mated in the morning were subjected to either a 6-h advance shift or a 6-h delay shift of the LD cycle on Days 5-14 of gestation. For the last 2 days of gestation the hamsters were kept in constant dim light and observed every hour to determine the time of birth. Hamsters mated in the evening gave birth an average of 4.8 h before those mated in the morning, and the hamsters subjected to an advance shift gave birth an average of 8.1 h before those subjected to delay shift. The results show that 80-100% of births occur during the subjective day on Day 16 of gestation and that the minimum duration of gestation is 15 days and 2 h. The regulation of birth appears to involve two processes, an interval timer related to the time of conception and a circadian rhythm that is governed by the LD cycle.
在叙利亚仓鼠（金仓鼠）中研究了交配时间和光照-黑暗（LD）周期对分娩时间和妊娠期长度的影响。维持在14小时光照：10小时黑暗周期的仓鼠在傍晚或早晨交配2小时，并且在妊娠第5至14天将早晨交配的仓鼠组的LD周期提前6小时或延迟6小时。在妊娠的最后2天，仓鼠饲养在持续昏暗的光线下，每小时观察一次以确定出生时间。傍晚交配的仓鼠比早晨交配的仓鼠平均提前4.8小时分娩，提前移位的仓鼠比延迟移位的仓鼠平均提前8.1小时分娩。结果表明，80 - 100%的分娩发生在妊娠第16天的主观白天，并且妊娠期的最短持续时间为15天2小时。分娩的调节似乎涉及两个过程，一个与受孕时间相关的间隔定时器和一个由LD周期控制的昼夜节律。
