Malven P V
Neuroendocrinology. 1975;19(1):81-90. doi: 10.1159/000122428.
Plasma LH was significantly increased by electrical stimulation of the median eminence (ME) in ovariectomized and in estradiol-treated sheep. In untreated castrates, spontaneous discharges of LH occurred at regular intervals of approximately one hour (LH rhythm). When ME stimulations were initiated as early as 5-15 min following a spontaneous discharge, they increased LH as much as either ME stimulations initiated at other times or spontaneous discharges. These data failed to demonstrate any pituitary refractoriness to ME stimulation, and presumably to endogenous LH-releasing factor (LRF). Therefore, neural mechanisms involving rhythmic release of LRF were indicated. The chronic administration of estradiol inhibited the spontaneous discharges of LH, and subsequent ME stimulation increased plasma LH even more markedly than in untreated castrates.
在切除卵巢的绵羊和接受雌二醇处理的绵羊中，电刺激正中隆起（ME）可使血浆促黄体生成素（LH）显著增加。在未经处理的去势羊中，LH的自发性释放每隔约一小时有规律地发生（LH节律）。当在自发性释放后早至5 - 15分钟开始ME刺激时，其增加LH的程度与在其他时间开始的ME刺激或自发性释放一样多。这些数据未能证明垂体对ME刺激以及可能对内源性促黄体生成素释放因子（LRF）有任何不应性。因此，提示存在涉及LRF节律性释放的神经机制。长期给予雌二醇可抑制LH的自发性释放，随后的ME刺激使血浆LH升高得甚至比未经处理的去势羊更明显。
