OVARIAN HORMONE REGULATION OF LHRH BIOSYNTHESIS

LHRH 生物合成的卵巢激素调节

• 批准号: 6344052
• 负责人: SANDRA L PETERSEN
• 金额: $ 3.64万
• 依托单位: UNIVERSITY OF MASSACHUSETTS AMHERST
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-03-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6344052
• 关键词: GABA receptor; estradiol; estrogen receptors; fos protein; genetic transcription; gonadotropin releasing factor; hormone regulation /control mechanism; immunocytochemistry; in situ hybridization; laboratory rat; luteinizing hormone; mifepristone; muscimol; neuroendocrine system; norepinephrine; peptide hormone biosynthesis; progesterone; solution hybridization; tyrosine 3 monooxygenase

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.

这项研究的长期目标是确定 雌二醇(E_2)和孕酮(P_4)调节LHRH的机制(S) 生物合成和浪涌释放。E2和P4差异调节两个 LHRH神经元活性变化的细胞内标志物 LHRH神经元亚群--雌二醇诱导的LHRH基因表达增加 LHRH峰释放开始前的转录和P4依赖 Fos的表达在峰开始时增加。因为很少人，如果 Any，LHRH神经元含有雌激素受体(ER)或孕激素受体 (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(NA)和 GABA能可能就是这些传入系统。因此，在建议的 研究我们将测试新的假设，即NA的顺序变化 而GABA能信号直接调节类固醇特异性变化 LHRH合成、释放和改变神经细胞内标志物 功能。我们将首先确定雌二醇是否会引起NA的变化 释放前后LHRH基因表达增加。要做到这一点 我们将评估脑干神经元活动的变化 LHRH神经元，以及下丘脑内侧脑区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基因转录增加是否优先发生在 有AR的神经元及特异性AR拮抗剂能否阻断 这些神经元中的转录。最后，我们将确定是否 非配体依赖的PR激活减少GABA能信号转导到 LHRH神经元，以及这一信号是否被给予 P4，以Fos表达标记。为了实现这一目标，我们将测试 RU486能否阻止GABA周转率和水平的下降 先前观察到的谷氨酸脱羧酶(GAD)mRNA LHRH浪涌释放，P4是否进一步下降，是否变化 在GAD mRNA中优先出现在也表达PR的神经元中，并且 GABA受体激动剂是否阻断Fos的表达 在LHRH神经元中。这些研究将提供重要的新信息 关于传递类固醇的传入神经系统的身份 传递给LHRH神经元的信号。此外，他们获胜的基础是 LHRH细胞内调控机制的研究进展 生物合成和释放。这些信息将对以下方面至关重要- 也站在控制排卵的神经内分泌机制上 因为这些控制机制的改变导致早熟 青春期、下丘脑不孕症和更年期。因此，这一信息 对于开发更安全和更有效的避孕药具将是重要的 和治疗手段。