MOLECULAR BIOLOGY OF HORMONES THAT REGULATE REPRODUCTION

本项目的目标是研究 编码大脑和性腺激素的基因，参与控制 哺乳动物的繁殖。四种多肽荷尔蒙调节 垂体促性腺激素的合成和分泌已被描述。 这些是下丘脑肽促性腺激素释放激素(GnRH)， 相关性腺激素抑制素和激活素及其最新进展 描述了卵巢激素卵泡刺激素。抑制素、激活素和卵泡抑素 调节卵泡刺激素和促性腺激素释放激素的分泌 调节卵泡刺激素和促黄体生成素的分泌。 脑下垂体。因为卵泡刺激素和促黄体生成素在调节 性腺的配子生成和类固醇生成功能，这些调节 荷尔蒙可能对生殖系统的动态平衡很重要。 系统。我们已经从大鼠中分离出了所有这些多肽的cdna克隆。 激素：促性腺激素释放激素、卵泡刺激素以及 抑制素/激活素。我们已经使用这些cDNA来检测 原位杂交法检测生殖组织中相应的mRNAs 并已开始探索这些基因的调控 在大鼠发情周期和怀孕期间。我们现在建议 将这些研究扩展到两个方向。首先，我们计划探索 这些基因被调控的分子机制。我们将完成 体内实验检测促性腺激素释放激素、抑制素和激活素mRNA的变化 在发情周期和对特定激素的反应中的水平。我们 将发展体外分析，包括卵巢器官培养和原代培养 大鼠颗粒细胞培养，以直接检测类固醇和 多肽激素对抑制素基因表达的影响。颗粒细胞会 也可用于抑制素和激活素基因的转染研究 将对监管要素进行描述。第二，我们计划研究 这些基因在几种小说中表达的生物学意义 纸巾。抑制素/激活素β链mRNA在不同的组织中被发现 组织，包括大脑、脑下垂体、造血系统和 胎盘。这特别耐人寻味，因为它与 生长分化中的转化生长因子-β家族 监管者。我们将研究在发育过程中抑制素/激活素 β链基因在这些组织中表达，并决定是否 基因的调节方式与在性腺中观察到的方式相似。我们 还将检测大鼠性腺外卵泡抑素基因的表达， 根据我们最近的观察，该基因在 妊娠早期的蜕膜组织。为了帮助这些研究，我们将 产生针对激活素和卵泡抑素的免疫试剂 蛋白质。我们希望这些实验能加深我们对 这些荷尔蒙在调节正常生殖方面发挥作用，并提供 一个框架，用于检查他们活动中的变化可能会如何导致 生殖障碍或功能障碍。

The goal of this project is to examine the expression and regulation of genes encoding brain and gonadal hormones that are involved in controlling mammalian reproduction. Four polypeptide hormones that modulate the synthesis and secretion of the pituitary gonadotropins have been described. These are the hypothalamic peptide gonadotropin-releasing hormone (GnRH), the related gonadal hormones inhibin and activin, and the recently described ovarian hormone follistatin. Inhibin, activin, and follistatin regulate the secretion of follicle-stimulating hormone (FSH) and GnRH regulates the secretion of FSH and lutienizing hormone (LH) from the pituitary. Because FSH and LH play a crucial role in modulating the gametogenic and steroidogenic functions of the gonads, these regulatory hormones are likely to be important for homeostasis in the reproductive system. We have isolated cDNA clones from the rat for all of these peptide hormones: GnRH, follistatin, and the alpha- and beta-chains of inhibin/activin. We have used these cDNAs to examine expression of the corresponding mRNAs in reproductive tissues using in situ hybridization histochemistry, and have begun to explore the regulation of these genes during the rat estrous cycle and during pregnancy. We now propose to extend these studies in two directions. Firstly, we plan to explore the molecular mechanisms by which these genes are regulated. We will complete in vivo experiments to examine changes in GnRH, inhibin, and activin mRNA levels during the estrous cycle and in response to specific hormones. We will develop in vitro assays, including ovarian organ cultures and primary rat granulosa cell cultures, to directly examine the effects of steroid and polypeptide hormones on inhibin gene expression. The granulosa cells will also be utilized for transfection studies in which inhibin and activin gene regulatory elements will be characterized. Secondly, we plan to examine the biological significance of expression of these genes in several novel tissues. The inhibin/activin beta-chain mRNA has been found in diverse tissues including the brain, pituitary, hematopoietic system, and the placenta. This is particularly intriguing in light of its similarity to the transforming growth factor-beta family of growth and differentiation regulators. We will investigate when in development the inhibin/activin beta-chain gene is expressed in these tissues, and determine whether the gene is regulated in a manner similar to that observed in the gonads. We will also examine extra-gonadal expression of the rat follistatin gene, pursuing our recent observation that this gene is highly expressed in decidual tissue early in pregnancy. To aid in these studies, we will generate immunological reagents specific for the activin and follistatin proteins. We expect these experiments to enhance our understanding of the roles these hormones play in regulating normal reproduction, and to provide a framework for examining how alterations in their activities might lead to reproductive disorders or dysfunction.