NEUROENDOCRINE GENES GOVERNING REPRODUCTION

这项研究的目的是了解 促性腺激素释放激素（GnRH）和阿黑皮素原（POMC） 参与雄性生殖的神经元。 中的单元格数组 下丘脑和前脑分泌GnRH，协调释放 垂体促性腺激素并最终控制睾丸功能。 大脑中的其他神经递质系统，包括 内源性阿片样物质家族（例如，β-内啡肽，来自POMC）和 兴奋性氨基酸谷氨酸，处理激素信号（例如， 睾丸激素）从睾丸，反过来，调节分泌 GnRH细胞的活性。 我们的第一个目标是研究睾丸激素 调节GnRH细胞内基因产物的合成。 这里我们 将集中在促性腺激素释放激素前体加工酶[羧肽酶H（CPH）和 α-酰胺化酶（PAM）]和谷氨酸受体（GluR-K1型）。 使用双重原位杂交，我们将绘制出 在解剖学定义的子集内编码CPH、PAM和GluR-K1的基因 的GnRH神经元，并检查其调节睾酮。 如果我们找到 睾丸激素会影响一个或多个基因的表达， 我们将继续测试这一假设，即睾丸激素对 促性腺激素分泌可归因于促性腺激素释放激素原加工的变化 或受体介导的对谷氨酸敏感性的改变。 我们将 通过将GnRH启动子与CPH的结构基因偶联， PAM或GluR-K1，并使用这些构建体来创建和研究转基因小鼠 在GnRH内表达这些嵌合基因之一的多个拷贝 神经元 我们的第二个目标是了解更多的分子生理学 睾丸激素敏感的POMC神经元的数量。 我们和其他人 先前已经表明，弓状核中的POMC神经元是 功能上是异质的，但是什么样的分子特征决定了 这种异质性，以及基因产物，除了POMC本身， 在这些神经元中的调节是未知的。 我们将在原地使用双 测量POMC mRNA和芳香酶或雌激素受体mRNA杂交 为了研究这些基因是如何被类固醇调节的， 在解剖学上定义的POMC神经元子集中。 我们相信这项工作 将促进细胞神经内分泌学知识的提高， 了解人类生殖相关临床问题的线索。

The goal of this research is to understand the molecular physiology of gonadotropin-releasing hormone (GnRH) and pro-opiomelanocortin (POMC) neurons involved in male reproduction. An array of cells in the hypothalamus and forebrain secretes GnRH, which coordinates the release of the pituitary gonadotropins and ultimately governs testicular function. Other neurotransmitter systems in the brain, including members of the endogenous opioid family (e.g., beta-endorphin, from POMC) and the excitatory amino acid glutamate, process hormonal signals (e.g., testosterone) from the testis which, in turn, modulate the secretory activity of GnRH cells. Our first objective is to learn how testosterone regulates the synthesis of gene products within the GnRH cell. Here, we will focus on the proGnRH processing enzymes [carboxypeptidase H (CPH) and alpha-amidating enzyme (PAM)] and the glutamate receptor (GluR-K1 type). Using double in situ hybridization, we will map the distribution of the genes coding for CPH, PAM, and GluR-K1 within anatomically defined subsets of GnRH neurons and examine their regulation by testosterone. If we find that testosterone influences the expression of one or more of these genes, we will proceed to test the hypothesis that the effect of testosterone on gonadotropin secretion can be attributed to changes in pro-GnRH processing or alterations in receptor-mediated sensitivity to glutamate. We will approach this by coupling the GnRH promoter to the structural gene for CPH, PAM or GluR-K1 and use these constructs to create and study transgenic mice expressing multiple copies of one of these chimeric genes within GnRH neurons. Our second objective is learn more about the molecular physiology of testosterone-sensitive POMC neurons in the hypothalamus. We and others have previously shown that POMC neurons in the arcuate nucleus are functionally heterogeneous, but what molecular characteristics determine this heterogeneity and how gene products, in addition to POMC itself, are regulated within these neurons are unknown. We will use double in situ hybridization to measure POMC mRNA and aromatase or estrogen receptor mRNAs for the purpose of the studying how these genes are regulated by steroids within anatomically defined subsets of POMC neurons. We believe this work will foster improved knowledge of cellular neuroendocrinology and may offer clues to understanding clinical problems related to human reproduction.