Different growth hormone (GH) responses to GH-releasing peptide and GH-releasing hormone in hyperthyroidism

Different growth hormone (GH) responses to GH-releasing peptide and GH-releasing hormone in hyperthyroidism

Autor Ramos-Dias, João Carlos Autor UNIFESP Google Scholar
Pimentel, F. Google Scholar
Reis, A. F. Google Scholar
Lengyel, AMJ Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Resumo Altered GH responses to several pharmacological stimuli, including GHRH, have been found in hyperthyroidism. the mechanisms underlying these disturbances have not been fully elucidated. GH-releasing peptide-6 (GHRP-B) is a synthetic hexapeptide that specifically stimulates GH release both in vitro and in vivo. the mechanism of action of GHRP-6 is unknown, but it probably acts by inhibiting the effects of somatostatin on GH release. the aim of this study was to evaluate the effects of GHRP-6 on GH secretion inpatients with hyperthyroidism (n = 9) and in control subjects (n = 9). Each subject received GHRP-B (1 mu g/kg, iv), GHRK (100 mu g, iv), and GHRP-6 plus GHRH on 3 separate days. GH peak values (mean +/- SE; micrograms per L) were significantly lower in hyperthyroid patients compared to those in control subjects after GHRH alone (9.0 +/- 1.3 vs. 27.0 +/- 5.2) and GHRP-6 plus GHRH (22.5 +/- 3.5 vs. 83.7 +/- 15.2); a lack of the normal synergistic effect of the association of both peptides was observed in thyrotoxicosis. However, a similar GH response was seen in both groups after isolated GHRP-6 injection (31.9 +/- 5.7 vs. 23.2 +/- 3.9). in summary, we have shown that hyperthyroid patients have a normal GH response to GHRP-6 together with a blunted GH responsiveness to GHRH. Our data suggest that thyroid hormones modulate GH release induced by these two peptides in a differential way.
Idioma Inglês
Data 1996-04-01
Publicado em Journal of Clinical Endocrinology & Metabolism. Chevy Chase: Endocrine Soc, v. 81, n. 4, p. 1343-1346, 1996.
ISSN 0021-972X (Sherpa/Romeo, fator de impacto)
Editor Endocrine Soc
Extensão 1343-1346
Fonte http://dx.doi.org/10.1210/jcem.81.4.8636330
Direito de acesso Acesso restrito
Tipo Artigo
Web of Science WOS:A1996UD66600011
URI http://repositorio.unifesp.br/handle/11600/25579

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