STEROID-INITIATED EXOCYTOSIS IN SPERM

精子中类固醇引发的胞吐作用

基本信息

批准号：
2888944
负责人：
STANLEY MEIZEL
金额：
$ 24.16万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
1997
资助国家：
美国
起止时间：
1997-07-01 至 2002-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (Adapted from the Investigator's Abstract): Research in this three-times revised proposal is aimed at understanding the molecular steps involved in the initiation of the human sperm acrosome reaction. Progesterone secreted by follicular cells of the cumulus oophorus, is regarded as an in vivo acrosome reaction initiator by interacting with sperm membrane receptors to trigger an influx of Ca2+ and an efflux of Cl-. In addition, progesterone or a 3a-OH progesterone metabolite may bind or activate a unique human sperm GABAA-like receptor Cl- channel as well as bind to a receptor for a Ca2+ channel. The possibility exists that progesterone binds to one receptor/channel site and then activate the other receptor/channel by cross-talk. The application includes a series of studies concerned with the receptors, channels and ionic interactions through which progesterone initiates the human sperm acrosome reaction. The proposed specific aims will determine first whether a sperm GABAA-like receptor/Cl- channel is involved in progesterone-mediated Cl- efflux by using pharmacological agents which will determine differences between sperm and neuronal GABAA-like receptor/Cl-channels. A second aim is to determine which region of the sperm head the progesterone-mediated cytosolic Cl- efflux through the steroid receptor/Cl-channel begins during acrosome reaction. A third aim is to use available monoclonal antibodies against domains of the intracellular progesterone receptor and neuronal GABAA-like receptor/Cl- channel subunits to identify and further characterize the human sperm progesterone receptor(s). A fourth aim is to compare the effect of progesterone stereo isomers on Cl- and Ca2- flux to determine whether two separate progesterone receptors operate to elicit ion fluxes. A fifth aim is to determine whether human sperm can convert progesterone into an 3a-hydroxy metabolite known to activate neuronal GABAA-like receptor/Cl- channels and able to initiate the human acrosome reaction. A sixth aim is to determine whether Cl- efflux mediated by the GABAA-like receptor/Cl- channel controls progesterone-mediated Ca2+ influx. Finally, a seventh aim will use immunoelectron microscopy to determine the distribution of the human progesterone receptor(s) and human sperm GABAA-like receptor/Cl- channel at a high resolution level.

描述（改编自研究者的摘要）：这方面的研究三次修改的提案旨在理解分子步骤参与人类精子顶体反应的启动。黄体酮是由卵丘的滤泡细胞分泌的通过与精子相互作用被视为体内顶体反应引发剂膜受体触发 Ca2+ 流入和 Cl- 流出。在此外，孕酮或 3a-OH 孕酮代谢物可能会结合或激活独特的人类精子 GABAA 样受体 Cl 通道以及与 Ca2+ 通道受体结合。存在这种可能性黄体酮与一个受体/通道位点结合，然后激活另一个受体/通道位点通过串扰的受体/通道。该应用程序包括一系列与受体、通道和离子相互作用有关的研究黄体酮通过它启动人类精子顶体反应。这所提出的具体目标将首先确定精子是否具有 GABAA 样受体/Cl-通道参与孕酮介导的 Cl-流出使用药物来确定精子之间的差异和神经元 GABAA 样受体/Cl 通道。第二个目标是确定孕酮介导的胞质 Cl- 位于精子头部的哪个区域通过类固醇受体/Cl-通道的流出在顶体期间开始反应。第三个目标是使用现有的单克隆抗体来对抗细胞内孕酮受体和神经元 GABAA 样结构域受体/Cl-通道亚基来识别并进一步表征人类精子孕酮受体。第四个目的是比较效果黄体酮立体异构体对 Cl- 和 Ca2- 通量的影响，以确定是否有两种单独的黄体酮受体可引发离子通量。第五个目标目的是确定人类精子是否可以将黄体酮转化为黄体酮已知可激活神经元 GABAA 样受体/Cl- 的 3a-羟基代谢物通道并能够启动人类顶体反应。第六个目标是确定 Cl- 外流是否由 GABAA 样受体/Cl- 介导通道控制孕激素介导的 Ca2+ 流入。最后还有第七个目标将使用免疫电子显微镜来确定人类孕酮受体和人类精子 GABAA 样受体/Cl- 高分辨率水平的通道。