Moline M L, Albers H E, Moore-Ede M C
Biol Reprod. 1986 Oct;35(3):516-23. doi: 10.1095/biolreprod35.3.516.
LH surges occur 3 h later in intact anovulatory hamsters exposed to nonstimulatory photoperiods (6L:18D) for 8 wk than the proestrous LH surges from the same hamsters housed in 6L:18D for 3 weeks. In ovariectomized hamsters housed in 6L:18D for 3 wk, the LH surge was observed at the same time of day as in intact anovulatory hamsters at 8 wk. Implanting Silastic capsules containing estradiol benzoate (EB) advanced the timing of the daily surge of LH in ovariectomized hamsters housed in 6L:18D for 8 wk. EB also affected the magnitude of the LH surge in hamsters housed in 6L:18D for 8 wk. Two days after receiving EB implants, daily LH surges in anovulatory hamsters were suppressed by 75% and in ovariectomized "regressed" hamsters by 37%. This difference between groups was probably due to ovarian progesterone in intact animals. Estrogen is not required for LH surges in anovulatory hamsters but suppresses LH release when administered exogenously. The delay in the timing of the LH surge in anovulatory hamsters may result from the decline in estrogen resulting from short photoperiod exposure.
与在6L:18D光照周期下饲养3周的同一仓鼠的发情前期促黄体生成素（LH）峰相比，暴露于非刺激性光照周期（6L:18D）8周的完整无排卵仓鼠的LH峰出现时间晚3小时。在6L:18D光照周期下饲养3周的去卵巢仓鼠，其LH峰出现时间与8周龄的完整无排卵仓鼠相同。植入含有苯甲酸雌二醇（EB）的硅橡胶胶囊可使在6L:18D光照周期下饲养8周的去卵巢仓鼠每日LH峰的时间提前。EB还影响了在6L:18D光照周期下饲养8周的仓鼠LH峰的幅度。接受EB植入两天后，无排卵仓鼠的每日LH峰被抑制了75%，而去卵巢“退化”仓鼠的每日LH峰被抑制了37%。两组之间的这种差异可能是由于完整动物体内的卵巢孕酮所致。雌激素对于无排卵仓鼠的LH峰不是必需的，但外源性给予时会抑制LH释放。无排卵仓鼠LH峰时间的延迟可能是由于短光照周期暴露导致雌激素水平下降所致。
