Labhsetwar A P
J Reprod Fertil. 1975 Feb;42(2):341-50. doi: 10.1530/jrf.0.0420341.
A single subcutaneous injection of progesterone (0.5 mg/animal at 17.00 hours) on Day 3 of the cycle (Day 1 = day of vaginal discharge) interfered with ovulation and external vaginal discharge in all the animals. Lower doses were only partly active. Intravenous administration of LH, FSH or their combination at 14.00 hours on Day 4 failed to restore ovulation in such animals, implying a direct action of the administered progesterone on the ovary. A large dose of oestradiol benzoate (400 mug/animal) also proved inactive suggesting that progesterone did not interfere with ovulation solely through antioestrogenic action. Depletion of the pituitary LH stores normally found in association with ovulation and ovulatory peak of LH in plasma seen in control animals were not observed in the progesterone-treated hamsters suggesting a further action of progesterone at the pituitary-hypothalamic level in inhibiting ovulation. Administration of synthetic LRF (100 ng/animal, i.v.) on Day 4 to hamsters treated with progesterone caused an increase in plasma LH 15 min later which was comparable to the rise observed in control animals given a similar injection of LH-RF, implying lack of action of progesterone at the pituitary level. It is concluded that progesterone acts centrally, principally on the hypothalamus, and peripherally on the ovary to interfere with ovulation in hamsters. It is possible that the anovulatory state accompanying pregnancy results from these actions.
在发情周期的第3天（第1天=出现阴道分泌物的日子），于17:00给每只动物皮下注射一次孕酮（0.5毫克/只），结果所有动物的排卵和阴道外排液均受到干扰。较低剂量仅部分有效。在第4天的14:00静脉注射促黄体生成素（LH）、促卵泡生成素（FSH）或二者的组合，未能使这些动物恢复排卵，这意味着所注射的孕酮对卵巢有直接作用。大剂量的苯甲酸雌二醇（400微克/只）也被证明无效，这表明孕酮并非仅通过抗雌激素作用来干扰排卵。在孕酮处理的仓鼠中未观察到正常情况下与排卵相关的垂体LH储备的耗竭以及对照动物血浆中LH排卵峰，这表明孕酮在垂体 - 下丘脑水平还有进一步抑制排卵的作用。在第4天给用孕酮处理过的仓鼠静脉注射合成的促性腺激素释放因子（LRF，100纳克/只），15分钟后血浆LH升高，这与给类似注射LH - RF的对照动物中观察到的升高相当，这意味着孕酮在垂体水平没有作用。结论是，孕酮在中枢主要作用于下丘脑，在周围作用于卵巢，从而干扰仓鼠的排卵。伴随妊娠出现的无排卵状态可能是由这些作用导致的。
