Loss of luteinizing hormone surges induced by chronic estradiol is associated with decreased activation of gonadotropin-releasing hormone neurons.
Loss of luteinizing hormone surges induced by chronic estradiol is associated with decreased activation of gonadotropin-releasing hormone neurons.
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慢性雌二醇引起的黄体生成素激增的丧失与促性腺激素释放激素神经元的激活减少有关。
DOI：
10.1095/biolreprod66.4.1104
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发表时间：
2002
影响因子：
3.6
通讯作者：
Legan,SandraJ
中科院分区：
文献类型：
--
作者：
Tsai,Houng-Wei;Legan,SandraJ
去卵巢的年轻大鼠长期暴露于升高的循环雌二醇会导致类固醇诱导的黄体生成素高峰消失。这种促黄体生成素激增与CFos诱导的促性腺激素释放激素神经元的激活有关；因此，我们假设，慢性雌激素治疗通过减少促性腺激素释放激素神经元的激活而取消促黄体生成素激增。定期周期的大鼠被切除卵巢，并立即接受雌二醇植入或保持不治疗。雌二醇组分别于3d、2wk、4wk后1200h给予赋形剂或黄体酮，每小时采血7份，测定促黄体生成素水平。此后，所有大鼠都被灌流，并检查脑组织中CFos和GnRH的免疫细胞化学定位。未处理的去卵巢大鼠的GnRH神经元很少表达CFO。据报道，雌二醇处理3天引起的促黄体生成素释放峰与含CFos的GnRH神经元增加30%有关，孕酮增加了促黄体生成素峰的幅度和CFos免疫阳性的促性腺激素释放激素神经元的比例。根据假设，2周或更长时间的雌二醇引起的促黄体生成素高峰的消除与含有CFos的GnRH神经元百分比的减少是平行的，这种作用被黄体酮延迟。这些结果表明，慢性雌二醇部分地通过灭活促性腺激素释放激素神经元来消除类固醇诱导的促黄体生成素释放激素激增。
Chronic exposure of young ovariectomized rats to elevated circulating estradiol causes loss of steroid-induced LH surges. Such LH surges are associated with cFos-induced activation of GnRH neurons; therefore, we hypothesized that chronic estradiol treatment abolishes LH surges by decreasing activation of GnRH neurons. Regularly cycling rats were ovariectomized and immediately received an estradiol implant or remained untreated. Three days or 2 or 4 wk later, the estradiol-treated rats received vehicle or progesterone at 1200 h, and 7 hourly blood samples were collected for RIA of LH. Thereafter, all rats were perfused, and the brains were examined for immunocytochemical localization of cFos and GnRH. The GnRH neurons from untreated ovariectomized rats rarely expressed cFos. As reported, LH surges induced by 3 days of estradiol treatment were associated with a 30% increase in cFos-containing GnRH neurons, and progesterone enhanced both the amplitude of LH surges and the proportion of cFos-immunopositive GnRH neurons. As hypothesized, the abolition of LH surges caused by 2 or more weeks of estradiol was paralleled by a reduction in the percentage of cFos-containing GnRH neurons, and this effect was delayed by progesterone. These results suggest that chronic estradiol abolishes steroid-induced LH surges in part by inactivating GnRH neurons.