INTRACELLULAR REGULATION OF LH SUBUNIT MRNA EXPRESSION

这项建议中的实验目的是阐明 促性腺激素通过细胞内机制(第二信使)- 促性腺激素释放激素(GnRH)刺激α和 垂体合成黄体生成素所需的黄体生成素β亚基mRNAs 促性腺激素细胞。这些研究将在体外进行，并 促性腺激素释放激素(GnRH)刺激垂体的生理脉冲 促性腺激素。促性腺激素反应将通过以下方式评估 促性腺激素释放激素受体、α和黄体生成素βmRNA的测定 浓缩、黄体生成素储存和急性释放。的影响 催乳素和性腺激素对促性腺激素释放激素细胞反应的影响 要下定决心。涉及到的细胞内机制 传递促性腺激素释放激素信号刺激促黄体生成素亚单位基因 将通过测量信使核糖核酸反应来检查其表达 到绕过促性腺激素释放激素受体的药物。两者的影响 细胞内钙的持续和搏动性升高 环核苷酸和持续或间歇性刺激 蛋白激酶C对LH亚单位信使核糖核酸的影响 下定决心。通过将这些刺激的效果与 那些跟随GnRH脉冲的，我们的目的是阐明 参与信号传递的细胞内机制(S) 由GnRH受体结合启动。后续研究将 研究性腺激素是否通过修饰调节GnRH的作用 LH亚单位mRNA对第二信使的反应。其他 研究将探讨脱敏的机制。 通过持续的促性腺激素释放激素刺激，促黄体生成素的分泌。的作用 基因表达与促性腺激素释放激素的刺激能力 将检测脱敏细胞中的磷酸肌醇的水解度。 促性腺激素释放激素的作用机制对 对人类和动物生育能力的调节。脉搏跳动 促性腺激素释放激素刺激是维持促黄体生成素分泌和 持续的促性腺激素释放激素刺激会使黄体生成素的分泌减敏。 促性腺激素释放激素缺乏的特定症状在人类中被识别 GnRH可以恢复生育能力。 脉动的方式。长效促性腺激素释放激素激动剂脱敏 黄体生成素的释放正在被评估为潜在的避孕药。 对脉动的确切机制的阐明 促性腺激素释放激素刺激维持促黄体生成素的合成和分泌很重要 为发展未来的治疗方案，以 促进或抑制促性腺激素的分泌。

The aim of experiments in this proposal is to elucidate the intracellular mechanisms (2nd messengers) by which gonadotropin- releasing hormone (GnRH) stimulates expression of the alpha and LH beta subunit mRNAs required for LH synthesis by pituitary gonadotrope cells. The studies will be performed in vitro and physiologic pulses of GnRH used to stimulate pituitary gonadotropes. Gonadotrope responses will be assessed by measurement of GnRH receptors, alpha and LH beta mRNA concentration, LH storage and acute release. The effect of prolactin and gonadal steroids on cellular responses to GnRH will be determined. The intracellular mechanisms involved in transmitting the GnRH signal to stimulate LH subunit gene expression will be examined by measurement of mRNA responses to agents which bypass the GnRH receptor. The effects of both continuous and pulsatile elevation of intracellular calcium and cyclic nucleotides, and constant or intermittent stimulation of protein kinase C on LH subunit mRNA concentrations will be determined. By comparison of the effects of these stimuli with those following GnRH pulses, we aim to elucidate the intracellular mechanism(s) involved in transmission of the signal initiated by GnRH-receptor binding. Subsequent studies will examine if gonadal steroids regulate GnRH action by modifying LH subunit mRNA responses to the second messengers. Other studies will examine the mechanisms involved in desensitization of LH secretion by a continuous GnRH stimulus. The role of mRNA expression and the ability of GnRH to stimulate phosphoinositol hydrolysis in desensitized cells will be examined. The mechanisms of GnRH action have important implications for the regulation of fertility in humans and animals. A pulsatile GnRH stimulus is required to maintain LH secretion and continuous stimulation by GnRH desensitizes LH secretion. Specific syndromes of GnRH deficiency are recognized in humans and fertility can be restored by administration of GnRH in a pulsatile manner. Long acting GnRH agonists which desensitize LH release are being assessed as potential contraceptive agents. The elucidation of the exact mechanisms by which a pulsatile GnRH stimulus maintain LH synthesis and secretion are important for the development of future therapeutic regimens to both enhance or inhibit gonadotropin secretion.