Neuroendocrine studies on modulation of the function of the hypothalmo-pituitary-gonadal axis with nutrients

据报道，哺乳刺激是抑制哺乳期黄体生成素分泌的主要因素。哺乳刺激可能会随着哺乳期的推进或母亲的生理状况而变化，例如，幼崽的数量和幼崽的发育程度。我们首先研究了电刺激乳腺神经是否可以替代哺乳坐位，其次研究了哺乳期坐位对去卵巢哺乳期大鼠黄体生成素分泌模式的影响。电刺激不仅乳房神经，而且隐神经和正中神经也使血浆催产素浓度升高。氯丙嗪滴定能抑制束缚应激引起的血浆催产素水平的升高，但不能阻止电刺激乳房、隐神经和正中神经后催产素水平的升高。没有递增的…当母亲与嘴巴紧闭不能哺乳乳头的幼崽在一起时，血浆催产素水平会更高。需要进一步的研究来区分催产素对电刺激乳腺神经的反应与对正中神经和隐神经刺激的反应。正常大鼠在哺乳期第10天或第20天，血浆黄体生成素的基线很低时，脉动性黄体生成素的分泌受到强烈的抑制。去卵巢大鼠第10天的基线与正常大鼠相当，第20天，6只去卵巢的哺乳期大鼠中有5只基线升高，出现搏动性分泌物。在第6天和第15天植入雌二醇的两只哺乳期大鼠在下午晚些时候都出现了每日的黄体生成素高峰。在哺乳第8天摘除幼鼠后，黄体生成素的平均水平和黄体生成素脉冲的频率和幅度逐渐增加。卵巢切除后，周期大鼠的黄体生成素脉冲频率无明显变化，但其平均水平和幅度有所增加。这些结果清楚地表明：1.哺乳后期，下丘脑-垂体水平的哺乳刺激对黄体生成素脉动性分泌的抑制作用消失。2.银杏叶不影响雌二醇诱导的促黄体生成素释放的机制。3.哺乳的坐骨神经抑制搏动性分泌的方式与卵巢类固醇不同。较少

The suckling stimulus has been reported to be a dominant factor suppressing LH secretion during lactation. The suckling stimulus could change with the advancement of lactation or physiologcal condition of mothers e.g. number of pups the degree of pups development. We, first, studied whether or not the electrical stimulation of the mammary nerve could be used as a substitute for the suckling sitmulus, and secondly, we studied effects of thesuckling sitmulus on the secretory pattern of lh in ovariectomized lactating rats throughout the lactating peruid.1. The electrical sitmulation of not only the mammary nerve but also the saphoenous and median nerves increased the plasme oxytocin concentration. Although chlorpromazine adminidtration was able to inhibit the increase of plasma oxytocin level in response to the immobilization stress, chlorpromazine administration failed to prevent the increase occurring after the electrical stimulation of the mammary, saphenous and median nerves. No incre … More ase in the plasma oxytocin levels when the mother was placed with pups whose mouths were sealed not to suckle the teat. Further studies are required to discriminate the oxytocin response to the electrical stimulation of the mammary nerve from that to the sitmulation of the median and saphenous nerves.2. Pulsatile LH secretion was strongly suppressed on either day 10 or 20 of lactation in intact rats in which the base line of plasma LH was kept very low. In ovariectomized rats the base line was kept as low as that observed in intact rats on day 10 day 20 the base line raised and pulsatile secretion appeared in 5 out of 6 ovraiectomized lactating rats. Daily LH surges occurred in the late afternoon in both lactating rats inplanted with estradiol on day 6 or 15. The mean LH level and the frequency and amplitude of LH pulses gradually increased after removal of pups on day 8 of lactation. In cycling rats the frequency of LH pulses was unchanged after ovariectomy, although the mean LH level and the amplitude of LH pulses increased. These results clearly indicate: 1. Suppression of pulsatile LH secretion by the suckling stimulus at the hypothalamo-pituitary level is removed in late lactation. 2. The mechanisms responsible for the estradiol induced LH surge are not impaired by the sucklig sitmulus. 3. The suckling sitmulus suppresses pulsatile secretion in a different manner from that of ovarian steroids. Less