Novel mechanisms of growth hormone regulation: growth hormone-releasing peptides and ghrelin

Novel mechanisms of growth hormone regulation: growth hormone-releasing peptides and ghrelin

Autor Lengyel, Ana Maria Judith Autor UNIFESP Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Resumo Growth hormone secretion is classically modulated by two hypothalamic hormones, growth hormone-releasing hormone and somatostatin. A third pathway was proposed in the last decade, which involves the growth hormone secretagogues. Ghrelin is a novel acylated peptide which is produced mainly by the stomach. It is also synthesized in the hypothalamus and is present in several other tissues. This endogenous growth hormone secretagogue was discovered by reverse pharmacology when a group of synthetic growth hormone-releasing compounds was initially produced, leading to the isolation of an orphan receptor and, finally, to its endogenous ligand. Ghrelin binds to an active receptor to increase growth hormone release and food intake. It is still not known how hypothalamic and circulating ghrelin is involved in the control of growth hormone release. Endogenous ghrelin might act to amplify the basic pattern of growth hormone secretion, optimizing somatotroph responsiveness to growth hormone-releasing hormone. It may activate multiple interdependent intracellular pathways at the somatotroph, involving protein kinase C, protein kinase A and extracellular calcium systems. However, since ghrelin has a greater ability to release growth hormone in vivo, its main site of action is the hypothalamus. In the current review we summarize the available data on the: a) discovery of this peptide, b) mechanisms of action of growth hormone secretagogues and ghrelin and possible physiological role on growth hormone modulation, and c) regulation of growth hormone release in man after intravenous administration of these peptides.
Palavra-chave Growth hormone
Growth hormone secretagogues
Ghrelin
Somatostatin
Hypothalamus
Idioma Inglês
Data de publicação 2006-08-01
Publicado em Brazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 39, n. 8, p. 1003-1011, 2006.
ISSN 0100-879X (Sherpa/Romeo, fator de impacto)
Publicador Associação Brasileira de Divulgação Científica
Extensão 1003-1011
Fonte http://dx.doi.org/10.1590/S0100-879X2006000800002
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000239936900002
SciELO S0100-879X2006000800002 (estatísticas na SciELO)
Endereço permanente http://repositorio.unifesp.br/handle/11600/3183

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