Kerdelhué B, Lenoir V, Toner J, Millar R P, Dutlow C M, Williams R F, Jones G S, Hodgen G D
Laboratoire de Neurobiologie de la Reproduction, Jouy-en-Josas.
C R Acad Sci III. 1990;311(13):479-85.
Estradiol-17 beta (E2 17 beta) is well known to evoke a preovulatory-like LH surge in ovariectomized monkeys even in the absence of the integrity of the hypothalamo-pituitary connections. LH release from the anterior pituitary (AP) is reliant on stimulation by hypothalamic GnRH which is derived from proteolytic cleavage of a precursor (designated Pro-GnRH-GAP) which also results in the production of an associated peptide (GAP). The present study examined the effects of E2 17 beta on the hypothalamic content of Pro-GnRH-GAP, GnRH and GAP while incidental observations revealed the presence of Pro-GnRH-GAP and its products in the AP. Changes in GnRH and GAP were closely related at all times after E2 17 beta treatment. However, the pattern of change in the hypothalamus and AP was inversely related. Pro-GnRH-GAP levels remained unchanged in the hypothalamus whereas in the AP the peptide increased markedly (48 hrs. post E2 17 beta) prior to the LH surge and declined to low levels (72 hrs. post E2 17 beta) at the time of the LH surge. The increase in Pro-GnRH-GAP in the AP that precedes the rise in GnRH and accompanying LH surge by 24 hrs. strongly indicates that AP GnRH is more important than hypothalamic GnRH for the mediation of the E2 17 beta-induced LH surge in female primate.
众所周知，即使在缺乏下丘脑 - 垂体连接完整性的情况下，雌二醇 - 17β（E2 17β）也能在去卵巢的猴子中诱发类似排卵前的促黄体生成素（LH）高峰。垂体前叶（AP）释放LH依赖于下丘脑促性腺激素释放激素（GnRH）的刺激，GnRH由一种前体（称为Pro - GnRH - GAP）的蛋白水解裂解产生，同时还会产生一种相关肽（GAP）。本研究检测了E2 17β对下丘脑Pro - GnRH - GAP、GnRH和GAP含量的影响，同时偶然观察发现AP中存在Pro - GnRH - GAP及其产物。E2 17β处理后的所有时间，GnRH和GAP的变化都密切相关。然而，下丘脑和AP中的变化模式呈负相关。下丘脑Pro - GnRH - GAP水平保持不变，而在AP中，该肽在LH高峰前显著增加（E2 17β处理后48小时），并在LH高峰时降至低水平（E2 17β处理后72小时）。AP中Pro - GnRH - GAP在GnRH升高和伴随的LH高峰前24小时增加，这强烈表明在雌性灵长类动物中，AP GnRH比下丘脑GnRH对介导E2 17β诱导的LH高峰更为重要。
