OVARIAN HORMONE REGULATION OF LHRH BIOSYNTHESIS

这项研究的长期目标是确定 雌二醇（E2）和孕酮（P4）调节LHRH的机制 生物合成和激增释放。 E2和P4分别调节两个 LHRH神经元活性变化的细胞内标记物， LHRH神经元亚群--E2诱导的LHRH基因表达增加 转录前LHRH浪涌释放和P4依赖性 在激增开始时Fos表达增加。 因为很少，如果 任何LHRH神经元含有雌激素受体（ER）或孕酮受体 (PR)这些细胞内事件必须由传入神经元介导， 系统. 最近的间接证据表明，去甲肾上腺素能（NA）和 GABA能可能是这些传入系统。 因此，在拟议的 研究中，我们将测试新的假设，连续变化的NA 和GABA能信号直接调节类固醇特异性变化， LHRH的合成和释放以及改变神经元的细胞内标记物 功能 我们将首先确定E2是否诱导NA的变化， 在LHRH基因表达增加时释放。 这么做 我们将评估脑干神经元活动的变化， LHRH神经元和NA周转率的变化， LHRH神经元 我们将使用双标记原位杂交来确定 LHRH基因转录的增加是否优先发生在 神经元与AR和特定的AR拮抗剂是否可以阻断 这些神经元中的转录。 最后，我们将确定 PR的配体非依赖性激活降低GABA能信号传导， LHRH神经元，以及这种信号是否通过给予 P4，以Fos表达为标志。 为了实现这一目标，我们将测试 RU 486是否阻断GABA周转率和水平的下降， 之前观察到的谷氨酸脱羧酶（GAD）mRNA LHRH激增释放，P4是否促进这些下降，是否改变 在GAD中，mRNA优先出现在也表达PR的神经元中， GABA受体激动剂是否阻断Fos表达 在LHRH神经元中。这些研究将提供重要的新信息 关于类固醇激素的传入神经系统的身份 LHRH神经元的信号。 此外，他们赢得了形式的基础， LHRH细胞内调节机制的研究进展 生物合成和释放。 这一信息将是至关重要的- 控制排卵的神经内分泌机制，以及 因为这些控制机制的改变导致早熟， 青春期、下丘脑性不孕症和更年期。 因此，这些信息 将对开发更安全、更有效的避孕药非常重要 和治疗方式。

The long-term objective of this research is to determine the mechanism(s) by which estradiol (E2) and progesterone (P4) regulate LHRH biosynthesis and surge release. E2 and P4 differentially regulate two intracellular markers of changes in LHRH neuronal activity in a subpopulation of LHRH neurons--an E2-induced increase in LHRH gene transcription before the onset of LHRH surge release and a P4-dependent increase in Fos expression at the onset of the surge. Because few, if any, LHRH neurons contain estrogen receptors (ER) or progestin receptors (PR), these intracellular events must be mediated by afferent neuronal systems. Recent indirect evidence suggests that noradrenergic (NA) and GABAergic may be these afferent systems. Therefore, in the proposed studies we will test the novel hypothesis that sequential changes in NA and GABAergic signalling directly regulate steroid-specific changes in LHRH synthesis and release and alter intracellular markers of neuronal function. We will first determine whether E2 induces changes in NA release around the time of increased LHRH gene expression. To do this we will assess changes in the activity of brainstem neurons that supply LHRH neurons, and changes in NA turnover rates in the region containing LHRH neurons. We will use dual-label in situ hybridization to determine whether increases in LHRH gene transcription occur preferentially in neurons with ARs and whether specific AR antagonists can block transcription in these neurons. Finally, we will determine whether ligand-independent activation of PR decreases GABAergic signalling to LHRH neurons, and whether this signal is amplified by administration of P4 and marked by Fos expression. To accomplish this goal, we will test whether RU486 blocks the decline in GABA turnover rates and in levels of glutamic acid decarboxylase (GAD) mRNA previously observed before LHRH surge release, whether P4 furthers these declines, whether changes in GAD mRNA occur preferentially in neurons that also express PR, and whether GABA receptor agonists block the appearance of Fos expression in LHRH neurons. These studies will provide important new information on the identity of the afferent neuronal systems that transduce steroid signals to LHRH neurons. In addition, they win form the basis for future studies on the intracellular mechanisms regulating LHRH biosynthesis and release. This information will be critical for under- standing the neuroendocrine mechanisms controlling ovulation, as well as alterations in these control mechanism that result in precocious puberty, hypothalamic infertility and menopause. Thus, this information will be important for developing safer and more effective contraceptives and therapeutic modalities.