GENE EXPRESSION IN NORADRENERGIC NEURONS AFTER COITUS & GONADECTOMY

下丘脑去甲肾上腺素(NE)在脑出血中起重要作用。 基础和性交后促性腺激素释放激素的分泌 促性腺激素释放激素(GnRH)/黄体生成素(LH)分泌 外源性去甲肾上腺素刺激两性性交GnRH/LH的释放 在雌性体内诱导伴随的内源性NE/GnRH/LH释放，但 在男性身上不是。这项研究的目的是确定 去甲肾上腺素能神经元的合成和/或摄取发生改变 性腺切除减少性类固醇激素后或增加性激素后 性交激活下丘脑-垂体性腺。我们克隆了兔子 酪氨酸羟化酶(TH)和去甲肾上腺素(NE)基因特异的cDNA探针 转运蛋白(Net)，这是调节NE合成和吸收的两个关键因素， 并建立了灵敏的核糖核酸酶保护试验 个体特定去甲肾上腺素能细胞群的mRNA水平 兔子。性腺切除三周后，血中黄体生成素和黄体生成素水平 去甲肾上腺素能神经元TH和Net的mRNAs水平在 在完好无损的男性和女性身上都有类似的价值。一种比较 在性交激活大脑后，这三个相同的参数 去甲肾上腺素-垂体促黄体生成素系统在 15岁至15岁女性血液中黄体生成素、神经元TH和Net基因的表达水平 交配后240分钟，TH基因表达水平下降更多 快于信使核糖核酸的净值。与雌性形成鲜明对比的是，没有 血中促黄体生成素、神经元TH或Net基因表达水平的变化 雄兔的性交。这些观察表明，这两种反馈 性激素对基础促黄体生成素分泌和性交诱导的调节 NE/GnRH/LH释放可能涉及转录/翻译过程 在NE分泌神经元内。然而，一个明显的性别差异 存在于性交激活的去甲肾上腺素能神经元系统中 男性的这个神经内分泌轴没有反应。加在一起， 这一信息表明去甲肾上腺素的合成和再摄取是两个关键 交配调节促性腺激素释放激素/促黄体生成素分泌的因素 雌性，以及雄性和雌性兔子的性腺类固醇。

Hypothalamic norepinephrine (NE) plays an important role in the secretion of basal and postcoital gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) secretion because central infusion of exogenous NE stimulates GnRH/LH release in both sexes and coitus induces a concomitant endogenous NE/GnRH/LH release in females, but not in males. The aims of this study were to determine whether noradrenergic neuronal synthesis and/or uptake were altered either after reduction of sex steroids by gonadectomy or after increased hypothalamohypophyseal gonadal activation by coitus. We cloned rabbit gene specific cDNA probes of tyrosine hydroxylase (TH) and NE transporter (NET), two key factors regulating NE synthesis and uptake, and established a sensitive ribonuclease protection assay to measure mRNA levels in specific noradrenergic cell groups in individual rabbits. Three weeks after gonadectomy, blood levels of LH and noradrenergic neuronal levels of TH and NET mRNAs were elevated over similar values in both intact males and females. A comparison of these same three parameters after coital activation of the brain noradrenergic-pituitary LH system revealed concomitant increases in blood LH and neuronal TH and NET mRNA levels in females between 15 and 240 min after copulation, except that TH mRNA levels declined more rapidly than NET mRNA values. In marked contrast to females, no changes in blood LH, neuronal TH or NET mRNA levels occurred after coitus in male rabbits. These observations suggest that both feedback regulation of sex steroids on basal LH secretion and coitus-induced NE/GnRH/LH release may involve transcriptional/translational processes within NE-secreting neurons. However, a clear gender difference exists in the coitally activated noradrenergic neuronal system since this neuroendocrine axis in males does not respond. Taken together, the information suggests that NE synthesis and reuptake are two key factors in mediating the regulation of GnRH/LH secretion by coitus in females, and by gonadal steroids in both male and female rabbits.