Comparative Physiology of Pituitary Hormones: Regulation of Secretion

本提案的目标是获得关于 垂体激素的合成和分泌机制 在变温脊椎动物中受到调节。 控制促甲状腺激素（TSH）和促性腺激素的下丘脑因子 (FSH和LDH分泌以及调节 爬行动物和两栖动物的垂体对这些因素的敏感性。 的 小海龟将作为爬行动物系统的模型，牛蛙将作为 将作为一个两栖模型，与其他有限的比较 命令 A. 促甲状腺激素分泌：促甲状腺激素的调节将集中在作用， 下丘脑三肽，促甲状腺激素释放激素（TRH），其 在两栖动物和爬行动物中的作用知之甚少。 我们还将 检查大脑中潜在的刺激物和抑制物的作用 和外周，特别是甲状腺激素，可能会调节垂体 对TRH的反应。 对垂体的急性和慢性热效应 反应性将在外源控制的背景下进行研究。 将尝试分析垂体生长激素和催乳素 所有研究中伴随的反应，以及体外甲状腺TSH 将并行测量灵敏度。 B。 促性腺激素分泌：促性腺激素调节的研究 将有两个焦点：1）类固醇在调节垂体 对促性腺激素释放激素的敏感性将在 与个体发育和维持两性异形的关系 对这种下丘脑肽的反应。 2)注意力将 首次针对非甾体性腺激素的作用， 分泌物（基于哺乳动物的Escherichin）在差异调节 垂体FSH和LH分泌。 这些研究应该为理解 下丘脑-垂体调节的演变及其与 外周内分泌靶点的研究。

The goal of this proposal is to obtain basic information on the mechanisms by which the synthesis and secretion of pituitary hormones are regulated in ectothermal vertebrates The initial focus will be on hypothalamic factors that control thyrotropin (TSH) and gonadotropin (FSH and LDH secretion and on peripheral factors that modulate pituitary sensitivity to these factors in reptiles and amphibians. The young turtle will serve as a model reptilian system and the bullfrog will serve as an amphibian model, with limited comparisons with other orders. A. TSH Secretion: TSH regulation will focus on the role of the hypothalamic tripeptide, thyrotropin-releasing hormone (TRH), whose role in amphibians and rrptiles is poorly understood. We will also examine actions of potential stimulators and inhibitors from the brain and periphery, especially thyroid hormones, that may modulate pituitary responsiveness to TRH. Acute and chronic thermal effects on pituitary responsiveness will be examined in the context of exogeous control. Attempts will be made to analyze pituitary growth hormone and prolactin responses concomitantly in all studies, and in vitro thyroidal TSH sensitivity will be measured in parallel. B. Gonadotropin Secretion: Studies on the regulation of gonadotropin will have two foci:1) The role of steroids in modulating pituitary sensitivity to gonadotropin releasing hormone will be studied in relation to the ontogeny and maintenance of sexual dimorphism in responsiveness to this hyhpothalamic peptide. 2) Attention will be directed for the first time to the role of nonsteroidal gonadal secretions (based on mammalian inhibin) in differentially modulating pituitary FSH and LH secretion. These studies should provide a foundation for understanding the evolution of hypothalamo-pituitary regulation and its integration with peripheral endocrine targets in ectothermal tetrapods.