Interaction of prolactin, ANPergic, oxytocinergic and adrenal systems in response to extracellular volume expansion in rats

Autor(es)

Durlo, F. V. ; Castro, M. ; Elias, L. L. K. ; Antunes-Rodrigues, J. ^[4]

• Tipo de documento: Artigo Científico
• Fonte: Experimental Physiology; v. 89, n. 5, p. 541-548, Sept. 2004.
• Área do conhecimento: Ciências Biológicas - Fisiologia
• Assunto(s): Sistema hipotálamo-hipofisário Glândulas suprarrenais Hormônios Fator natriurético atrial Substitutos do plasma Corticosterona

Resumo

The present study evaluated the effect of acute extracellular volume expansion (EVE) induced by intravenous injection of isotonic (0.15 M NaCl) or hypertonic saline (0.3 M NaCl) on prolactin, corticosterone, vasopressin, oxytocin and atrial natriuretic peptide (ANP) secretion. Male Wistar rats were treated with bromocriptine, sulpiride or dexamethasone. After isotonic and hypertonic EVE, the control group showed a significant increase in the plasma concentrations of prolactin, corticosterone, ANP and oxytocin. The increase in ANP and oxytocin levels in response to hypertonic EVE was more pronounced than to isotonic EVE. Bromocriptine and sulpiride treatments did not modify corticosterone, ANP and oxytocin responses to either isotonic or hypertonic EVE. The increases in prolactin and oxytocin, but not ANP, were blocked in dexamethasone pretreated rats. In conclusion, isotonic or hypertonic EVE induced an increase in the plasma concentrations of prolactin, corticosterone, ANP and oxytocin. The increases in ANP and oxytocin were independent of plasma concentrations of prolactin. The increases in prolactin and oxytocin were blocked by the inhibition of the hypothalamo-pituitary-adrenal (HPA) axis by dexamethasone. However, dexamethasone did not alter the increase in ANP secretion induced by isotonic or hypertonic EVE. Therefore, prolactin might participate in regulation of the hydroelectrolytic balance in mammals; however, in the present study, there was no evidence for direct interaction with ANPergic and oxytocinergic systems. In addition, the responses of prolactin and oxytocin induced by isotonic or hypertonic EVE are modulated by the HPA axis. (AU)

• Processo FAPESP: 00/00066-1 - Efeito da expansao do volume extracelular sobre a secrecao de prolactina e a modulacao pelo eixo hipotalamo-hipofise-adrenal.
• Beneficiário: Flavia Vendramini Durlo
• Modalidade de apoio: Bolsas no Brasil - Mestrado