Data/hora: 23/09/2024 18:52:47

Biblioteca(s): 	Embrapa Caprinos e Ovinos.	
Data corrente: 	16/06/2017	
Data da última atualização: 	16/06/2017	
Autoria: 	THOMAS, G. B.; CUMMINS, J. T.; HAMMOND, J. M.; HORTON, R. J. E.; CLARKE, I. J.	
Título: 	Prolonged secretion of prolactin in response to thyrotrophin-releasing hormone after hypothalamo-pituitary disconnection in the ewe.	
Ano de publicação: 	1986	
Fonte/Imprenta: 	Journal of Endocrinology, v. 111, n. 3, p. 433-438, Dec. 1986.	
DOI: 	10.1677/joe.0.1110433	
Idioma: 	Inglês	
Conteúdo: 	Abstract: 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.	
Palavras-Chave: 	Pharmacolog; Releasing hormones; Time Factors.	
Thesaurus Nal: 	chlorpromazine; metoclopramide; Physiology; Pituitary gland; Prolactin; Sheep; Thyrotropin.	
Categoria do assunto: 	L Ciência Animal e Produtos de Origem Animal	
Registro original: 	Embrapa Caprinos e Ovinos (CNPC)	
Exemplares: 	CNPC - (33844-1) - ADD - AP - PP -  -  -  - DIS