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(Referência obtida automaticamente do SciELO, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

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Autor(es):
Cibele N. Peroni ; Cesar Y. Hayashida ; Nancy Nascimento ; Viviane C. Longuini ; Rodrigo A. Toledo ; Paolo Bartolini ; Cyril Y. Bowers ; Sergio P.A. Toledo
Número total de Autores: 8
Tipo de documento: Artigo Científico
Fonte: Clinics; v. 67, n. 3, p. -, 2012.
Resumo

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormonereleasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormonereceptors, were compared to those observed in the heterozygous (lit/&#43;) littermates and wild-type (&#43;/&#43;) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/&#43; mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a. (AU)

Processo FAPESP: 01/11091-0 - Modelos animais de terapia gênica: estudo da expressão prolongada do hormônio de crescimento em camundongos anões (little/little) e anões imunodeficientes (little/scid)
Beneficiário:Paolo Bartolini
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 09/15386-6 - Análise dos genes CDKN1A, CDKN1B, CDKN2B e CDKN2C, nas Neoplasias Endócrinas Múltiplas tipo 1 e 2
Beneficiário:Rodrigo de Almeida Toledo
Linha de fomento: Bolsas no Brasil - Pós-Doutorado