Prolonged secretion of prolactin in response to thyrotrophin-releasing hormone after hypothalamo-pituitary disconnection in the ewe.
Prolonged secretion of prolactin in response to thyrotrophin-releasing hormone after hypothalamo-pituitary disconnection in the ewe.
复制标题
母羊下丘脑-垂体断开后，促甲状腺激素释放激素的催乳素分泌延长。
DOI：
10.1677/joe.0.1110433
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
I. Clarke
中科院分区：
文献类型：
--
作者：
G. Thomas;J. Cummins;J. Hammond;R. J. Horton;I. Clarke
手术切断绵羊下丘脑与垂体的连接(HPD)为研究促性腺激素分泌的调控提供了一种有用的实验模型。本研究的目的是确定HPD母羊在刺激下丘脑或直接作用于脑下垂体时催乳素分泌的特点。催乳素对应激性刺激或多巴胺能拮抗剂甲氧氯普胺(20 mg静脉注射)的反应。或氯丙嗪(50 mg静脉注射)在完整动物(假HPD)中发现的HPD被HPD完全消除。注射TRH(100微克，静脉注射)导致两组母羊立即释放催乳素。在HPD绵羊中，血浆催乳素浓度在注射TRH后至少3小时内保持升高，而在假HPD绵羊中，血浆催乳素浓度在20分钟后开始下降。TRH后10分钟静脉注射溴隐亭(1 Mg)可抑制HPD绵羊对TRH的延长反应。结果支持催乳素在下丘脑水平对自身分泌产生短环反馈效应的假说。
Surgical disconnection of the ovine hypothalamus from the pituitary gland (hypothalamo-pituitary disconnection; HPD) has provided a useful experimental model for studying the control of gonadotrophin secretion. The objective of the present study was to define the characteristics of prolactin secretion using stimuli acting through the hypothalamus or directly on the pituitary gland in HPD ewes. Prolactin responses to either a stressful stimulus or the dopaminergic antagonists metoclopramide (20 mg i.v.) or chlorpromazine (50 mg i.v.) seen in intact animals (sham-HPD) were completely abolished by HPD. Injection of TRH (100 micrograms i.v.) caused an immediate release of prolactin in both groups of ewes. In the HPD ewes plasma prolactin concentrations remained raised for at least 3 h after TRH injection, whereas in sham-HPD ewes prolactin concentrations began to decline after 20 min. Administration of bromocriptine (1 mg i.v.) 10 min after TRH inhibited the prolonged response to TRH in HPD ewes. The results support the hypothesis that prolactin exerts a short-loop feedback effect on its own secretion at the hypothalamic level.