Gala R R, Haisenleder D J
Life Sci. 1984 Jan 9;34(2):179-85. doi: 10.1016/0024-3205(84)90588-5.
Experiments were performed to determine whether both prolactin (PRL) surges are required to maintain pseudopregnancy (PSP) in the rat. Vaginal cycles were followed and animals that exhibited 2-3 normal cycles were cervically stimulated electromechanically to induce PSP. In one set of experiments the afternoon PRL surge was blocked by i.p. injection of 100 micrograms of 2Br-alpha-ergocryptine (CB-154) at 1200 and 1600h while the nocturnal surge was blocked by injecting 100 micrograms of CB-154 at 2400 and 0400h immediately after cervical stimulation. Pseudopregnancy was maintained only in those animals receiving CB-154 injections in the afternoon. In another series of experiments the initial CB-154 injection, given to block either surge, was delayed for one day. Once again only the nocturnal surge was capable of maintaining PSP in all animals. For those animals who had an initial nocturnal surge but all subsequent nocturnal surges were blocked, the afternoon surge was able to support PSP in only 50% of the animals. In those animals whose afternoon PRL surge was blocked, the duration of the nocturnal surge was extended so that it provided 85% of the total PRL produced by control PSP animals. In those animals whose nocturnal surge was blocked, the duration of the afternoon surge was also extended, however, in this case the extended surge only accounted for 58% of the total PRL produced by control PSP animals. The results indicated that when the diurnal PRL surge was blocked the nocturnal surge was extended so that the amount of PRL released was nearly equivalent to the amount released by both surges, however, when the nocturnal surge was blocked the extension of the diurnal surge did not provide adequate PRL to maintain PSP in all animals.
进行实验以确定维持大鼠假孕（PSP）是否需要两种催乳素（PRL）高峰。跟踪阴道周期，对表现出2 - 3个正常周期的动物进行宫颈机电刺激以诱导假孕。在一组实验中，下午的PRL高峰在1200和1600时通过腹腔注射100微克2 - 溴 - α - 麦角隐亭（CB - 154）被阻断，而夜间高峰在宫颈刺激后立即于2400和0400时注射100微克CB - 154被阻断。仅在那些下午接受CB - 154注射的动物中维持了假孕。在另一系列实验中，为阻断任一高峰而进行的初始CB - 154注射延迟一天。再次，仅夜间高峰能够在所有动物中维持假孕。对于那些有初始夜间高峰但所有后续夜间高峰被阻断的动物，下午高峰仅能在50%的动物中支持假孕。在那些下午PRL高峰被阻断的动物中，夜间高峰的持续时间延长，使得它提供了对照PSP动物产生的总PRL的85%。在那些夜间高峰被阻断的动物中，下午高峰的持续时间也延长了，然而，在这种情况下，延长的高峰仅占对照PSP动物产生的总PRL的58%。结果表明，当白天的PRL高峰被阻断时，夜间高峰延长，使得释放的PRL量几乎等同于两个高峰释放的量，然而，当夜间高峰被阻断时，白天高峰的延长并没有提供足够的PRL在所有动物中维持假孕。
