EXPRESSION OF AN FSH ANALOG WITH A REROUTED SECRETION PATTERN IN TRANSGENIC MICE

描述（由申请人提供）：人垂体激素lutropin （LH）和卵泡激素（FSH）是糖蛋白异源二聚体家族的一部分，由一个共同的1亚基和一个激素特异性的¿亚基组成。它是决定每种激素的生物学特异性的亚基。这些蛋白质的一个关键特征是它们独特的分泌模式。LH是通过受调控的途径释放的，即通过促分泌剂释放，而FSH主要是组成型分泌。这些路径对于黄体生成素和卵泡刺激素在生殖中的协调作用是必不可少的。确定LH和FSH分类和贩运的决定因素一直是我实验室的主要重点。利用转染的垂体生长激素来源的GH3细胞，在LH¿亚基的羧基端鉴定了一个新的序列，该序列将LH引导到调节途径。此外，由FSH¿亚基和该肽组成的嵌合体被转移到受调节的途径。本R03试点提案的主要目的是验证这种FSH类似物可以在转基因小鼠的垂体中重新定向到调节途径的假设。因此，引导卵泡刺激素从其正常组成分泌到受调节途径的生理后果是什么？这些实验将使用人类FSH野生型或人类FSH类似转基因基因敲除FSH的小鼠。该模型的优点是可以在没有内源性小鼠卵泡刺激素背景的转基因小鼠中进行分类和功能检测。我们将研究切除垂体的分泌以及转基因小鼠通过调节途径分泌FSH的潜在生理后果。在体内改变垂体促性腺激素的能力代表了性腺功能障碍的潜在重要模型，并提供了一种检查人类生殖道正常和最终病理生理事件的新方法。

DESCRIPTION (provided by applicant): The human pituitary hormones lutropin (LH) and follitropin (FSH) are part of a family of glycoprotein heterodimers comprised of a common 1 subunit and a hormone-specific ¿ subunit. It is the ¿ subunit that determines the biological specificity of each hormone. A critical feature of these proteins is their unique secretory patterns. LH is released through a regulated pathway, i.e., it is released by secretagogue, whereas FSH is primarily secreted constitutively. These routings are essential for the coordinated roles of LH and FSH in reproduction. Identifying the determinants that account for the sorting and trafficking of LH and FSH has been a major focus of my laboratory. Using transfected pituitary somatotrope-derived GH3 cells, a novel sequence at the carboxyl end of the LH¿ subunit directing LH to the regulated pathway was identified. Moreover, a chimera comprised of the FSH¿ subunit and this peptide was diverted to the regulated pathway. The primary objective of this R03 pilot proposal is to test the hypothesis that this FSH analog can be rerouted to the regulated pathway in pituitaries of transgenic mice. Thus, what are the physiological consequences of directing FSH from its normal constitutive secretion to the regulated pathway? These experiments will employ FSH¿ knock-out mice using either the human FSH¿ wild type or the human FSH¿ analog transgenes. The advantage of this model is that the sorting and function can be examined in transgenic mice without the background of endogenous mouse FSH. We will examine the secretion from excised pituitaries and potential physiological consequences for the transgenic mice secreting FSH through the regulated pathway. The ability to reroute the pituitary gonadotropins in vivo represents a potentially important model for gonadal dysfunction and provides a novel way to examine normal and ultimately pathophysiological events in the human reproductive tract. PUBLIC HEALTH RELEVANCE: The studies proposed here are designed to study the link between the secretion pathways of FSH and LH and hormonal function. The data obtained from our work will aid in understanding the interplay between these hormones and the development of the follicle. In addition, pathologies in which there is hyper- or hypogonadism can likely be attributed to aberrant secretion of FSH and/or LH from the pituitary.