PROLACTIN--HYPOTHALAMIC-GONADAL-AUTOCRINE INTERACTIONS

催乳素是一种激素，它极大地影响生育和哺乳 因此，它在创造和 养育后代。 此外，催乳素还起着较为微妙的作用 在许多组织如免疫系统的功能中起作用， 肝脏和内分泌胰腺，这需要调整的需求， 怀孕和哺乳。 因此，对我们来说， 了解催乳素的总水平是如何调节的， 不同的繁殖阶段，因为不知道 催乳素是一个家族分子，分泌的催乳素是如何组成的？ 催乳素可能会发生变化。 对催乳素分泌的主要影响是 下丘脑/垂体后叶、自分泌/旁分泌和性腺。 在 本项目我们提出1）进一步研究自分泌抑制， 催乳素分泌的隔离，和2）这是如何整合的研究 控制下丘脑和性腺 对于后者，我们将 确定一个主要的下丘脑因子，多巴胺和 主要的性腺激素，雌激素，自分泌反馈系统。 在 在这方面，我们假设多巴胺对分泌的抑制是 独立于，而雌激素刺激分泌的工作通过， 调节自分泌机制。 另外，由于自分泌 调节是通过磷酸化状态的变化来完成的， 分泌的形式，我们将在这个过程中确定是否多巴胺和 雌激素影响分泌的催乳素的组成。 当研究 自分泌系统在隔离，剂量-反应曲线的准备工作， 非磷酸化和磷酸化催乳素和生理 其组合将允许我们确定什么设置（比例 的非磷酸化到磷酸化催乳素分泌）， 与显著的自分泌控制一致，因此我们可以预测， 根据我们的体内分析，当这种机制是最重要的， 其他控制因素必须占主导地位。 对于这些剂量反应 在研究中，我们将使用培养的GH 3细胞和原代大鼠垂体细胞。 在分析了天然磷酸化位点后， 用于这些研究的催乳素将在体外由重组 大鼠催乳素 多巴胺和雌激素的作用将在 体外对原代培养物和多巴胺激动剂的作用， 溴隐亭和拮抗剂氟哌啶醇将使用 结合体内体外方法。

Prolactin is a hormone which dramatically affects fertility and lactation and which therefore plays a crucial role in both the creation and nurturing of offspring. In addition, prolactin also plays a more subtle role in the functioning of many tissues such as the immune system, the liver and the endocrine pancreas, which need to adjust to the demands of pregnancy and lactation. It is therefore of immense importance for us to understand how total levels of prolactin are regulated at the different stages of reproduction and further, because there is not known to be a family of prolactin molecules, how the composition of secreted prolactin may change. The primary influences on prolactin secretion are hypothalamic/posterior pituitary, autocrine/paracrine, and gonadal. In this project we propose 1) further study of autocrine inhibition of prolactin secretion in isolation, and 2) a study of how this integrates with controls from the hypothalamus and gonads. For the latter we will determine the affects of a major hypothalamic factor, dopamine, and a major gonadal hormone, estrogen, ont he autocrine feedback system. In this regard, we hypothesize that dopamine inhibition of secretion is independent of, whereas estrogen stimulation of secretion works through, adjustments in the autocrine mechanism. Also, because autocrine adjustments are accomplished via shifts in the phosphorylation state of the forms secreted, we will in the process determine whether dopamine and estrogen affect the composition of secreted prolactin. When studying the autocrine system in isolation, dose-response curves to preparations of non-phosphorylated and phosphorylated prolactin and physiological combinations thereof will allow us to determine what settings (proportion of non-phosphorylated to phosphorylated prolactin secreted) are consistent with significant autocrine control so that we may predict, based on our in vivo analyses, when this mechanism is most important and when other controlling factors must predominate. For these dose response studies we will use GH3 cells and primary rat pituitary cells in culture. After analysis of the natural phosphorylation sites, phosphorylated prolactin for these studies will be produced in vitro from recombinant rat prolactin. The effects of dopamine and estrogen will be assessed in vitro on primary cultures and the effects of a dopamine agonist, bromocryptine, and an antagonist, haloperidol, will be assessed using a combined in vivo in vitro approach.