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MODULAÇAO DA SECREÇAO DO HORMONIO DE CRESCIMENTO PELA GHRELINA E OUTROS SECRETAGOGOS

(especial para SIIC © Derechos reservados)
Apresenta-se uma revisão sobre a ghrelina, os mecanismos de ação e possível papel fisiológico dos secretagogos de hormônio de crescimento e da ghrelina na secreção de hormônio de crescimento e os efeitos da administração endovenosa destes peptideos sobre a secreção de hormônio de crescimento no homem.
Autor:
Ana-maria j. Lengyel
Columnista Experto de SIIC

Institución:
Universidade Federal de São Paulo

Artículos publicados por Ana-maria j. Lengyel
Coautor
Larissa Bianca Paiva Cunha de Sá* 
Pós graduanda, Universidade Federal de São Paulo, São Paulo, Brasil*
Recepción del artículo
10 de Marzo, 2008 		Aprobación
4 de Abril, 2008
Primera edición
15 de Abril, 2009 		Segunda edición, ampliada y corregida
7 de Junio, 2021

MODULAÇAO DA SECREÇAO DO HORMONIO DE CRESCIMENTO PELA GHRELINA E OUTROS SECRETAGOGOS

Resumen
A secreção de hormônio de crescimento é modulada pelo hormônio liberador de hormônio de crescimento e pela somatostatina. Na ultima década foi descoberto um terceiro mecanismo de controle, envolvendo os secretagogos de hormônio de crescimento. A ghrelina é um peptídeo acilado, descoberto recentemente, que é produzido no estômago, porém também é sintetizado no hipotálamo. Este peptídeo é capaz de liberar hormônio de crescimento, além de aumentar a ingesta alimentar. A ghrelina endógena parece amplificar o padrão básico de secreção de hormônio de crescimento, ampliando a resposta do somatotrófo ao hormônio liberador de hormônio de crescimento. Este peptídeo estimula multiplas vias intracelulares interdependentes no somatotrófo, envolvendo a proteina quinase C, proteina quinase A, e sistemas moduladores de cálcio extracelular. Entretanto, como a liberação de GH induzida pela ghrelina in vivo é mais acentuada que in vitro, seu local de atuação predominante é no hipotálamo. No presente trabalho apresentamos uma revisão sobre a descoberta da ghrelina, os dados existentes sobre os mecanismos de ação e possível papel fisiológico dos secretagogos de hormônio de crescimento e da ghrelina na secreção de hormônio de crescimento e, finalmente, os efeitos da administração endovenosa destes peptideos sobre a secreção de hormônio de crescimento no homem.

Palabras clave
ghrelina, GH, secretagogos do hormônio de crescimento, GHS


Artículo completo
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Modulation of growth hormone secretion through the action of growth hormone secretagogues and ghrelin

Abstract
Growth hormone-releasing hormone and somatostatin modulate growth hormone secretion. A third mechanism has been discovered in the last decade, involving the action of growth hormone secretagogues . Ghrelin is a new acylated peptide mainly produced by the stomach, but also synthesized in the hypothalamus. This compound increases both growth hormone release and food intake. The relative roles of hypothalamic and circulating ghrelin on growth hormone secretion are still unknown. Endogenous ghrelin might amplify the basic pattern of growth hormone secretion, optimizing somatotroph responsiveness to growth hormone-releasing hormone. This peptide activates multiple interdependent intracellular pathways at the somatotroph, involving protein kinase C, protein kinase A and extracellular calcium systems. However, as ghrelin induces a greater release of growth hormone in vivo, its main site of action is the hypothalamus. In the current paper we review the available data on the discovery of this peptide, the mechanisms of action and possible physiological roles of growth hormone secretagogues and ghrelin on growth hormone secretion, and, finally, the regulation of growth hormone release in man after intravenous administration of these peptides.

Key words
ghrelin, growth hormone secretagogues

Clasificación en siicsalud
Artículos originales > Expertos de Iberoamérica >
página   www.siicsalud.com/des/expertocompleto.php/

Especialidades
Principal: Endocrinología y Metabolismo
Relacionadas: Bioquímica, Diagnóstico por Laboratorio, Medicina Interna, Pediatría



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Enviar correspondencia a:
Ana-Maria J. Lengyel, Universidade Federal de São Paulo Escola Paulista de Medicina, 04039-002, Rua Pedro de Toledo, 910, São Paulo, Brasil
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