Differential effects of estrogen and progesterone on levels of POMC mRNA levels in the arcuate nucleus: relationship to the timing of LH surge release.
Differential effects of estrogen and progesterone on levels of POMC mRNA levels in the arcuate nucleus: relationship to the timing of LH surge release.
复制标题
雌激素和孕激素对弓状核中 POMC mRNA 水平的不同影响：与 LH 激增释放时间的关系。
DOI：
10.1111/j.1365-2826.1993.tb00534.x
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发表时间：
1993
影响因子：
3.2
通讯作者：
McCrone,S
中科院分区：
文献类型：
--
作者：
Petersen,SL;Keller,ML;Carder,SA;McCrone,S
β-内啡肽被认为是 LHRH 神经元活动的重要抑制剂，并且在向 LHRH 神经元传递有关类固醇水平变化的信息方面发挥着作用。我们之前已经表明，编码β-内啡肽前体阿片黑皮质素原 (POMC) 的 mRNA 在发情周期期间发生波动，其中最显着的变化发生在发情前期。 POMC mRNA 水平在 LH 激增释放开始之前下降，但随后急剧上升并在激增期间保持较高水平。在本研究中，我们测试了以下假设：发情前期 LH 激增之前 POMC mRNA 水平的下降是由雌激素介导的，而在高峰期间则由黄体酮介导的。为了检验这一假设，我们比较了卵巢切除 (OVX) 和 OVX 雌激素 (E2) 治疗的大鼠之间以及 OVX E2 治疗的大鼠（有或没有黄体酮）之间 POMC mRNA 水平的变化。给予黄体酮后每小时检查一次动物，然后在 LH 激增期间每 4 小时检查一次。使用原位杂交组织化学，我们发现 E2 在 LH 激增之前降低 OVX 大鼠中 POMC mRNA 水平，并在 LH 激增期间进一步抑制其水平。与单独使用 E2 治疗的动物相比，黄体酮提前了 LH 激增开始的时间和 POMC mRNA 水平下降的时间。在短暂下降后，这些黄体酮治疗的动物中 POMC mRNA 水平上升，并在 LH 激增期间保持升高状态。这些结果支持这样的假设：黄体酮乘以 LH 激增，并通过对弓状核 β-内啡能神经元的活动施加双相效应，将其出现限制在一天内。
Beta‐endorphin is thought be an important inhibitor of LHRH neuronal activity and also to play a role in conveying information about changes in steroid levels to LHRH neurons. We have previously shown that the mRNA encoding the precursor of ß‐endorphin, proopiomelanocortin (POMC), fluctuates during the estrous cycle with the most dramatic changes occurring on proestrus. POMC mRNA levels decline before the onset of LH surge release but then dramatically rise and remain elevated during the surge. In the present studies we tested the hypothesis that the decline in POMC mRNA levels immediately before the proestrous LH surge is mediated by estrogen and the rise during the surge by progesterone. To test this hypothesis, we compared changes in POMC mRNA levels between ovariectomized (OVX) and OVX estrogen (E2)‐treated rats and between OVX E2‐treated rats with and without progesterone. Animals were examined at hourly intervals after the administration of progesterone, then at every 4h during the LH surge. Usingin situhybridization histochemistry, we found that E2decreased POMC mRNA levels in OVX rats before the onset of the LH surge and further suppressed levels during the surge. Compared to animals treated with E2alone, progesterone advanced the time at which both the LH surge began and the time at which POMC mRNA levels declined. After a transient decline, POMC mRNA levels rose in these progesterone‐treated animals and remained elevated throughout the period of the LH surge. These results support the hypothesis that progesterone times the LH surge and limits its appearance to one day by exerting a biphasic effect on the activity of ß‐endorphinergic neurons of the arcuate nucleus.