Galanin Stimulates Glucocorticoid Secretion in Rats through a Receptor-dependent Activation of the Adenylate Cyclase/Protein Kinase A-dependent Signaling Pathway
1998; Elsevier BV; Volume: 19; Issue: 5 Linguagem: Inglês
10.1016/s0196-9781(98)00028-x
ISSN1873-5169
AutoresG. Mazzocchi, Piera Rebuffat, Giuseppe Gottardo, L K Malendowicz, Gastone G. Nussdorfer,
Tópico(s)Hypothalamic control of reproductive hormones
ResumoGalanin, a 29-amino acid peptide widely distributed in the central and peripheral nervous systems, was found to induce a concentration-dependent increase in corticosterone secretion and cyclic-AMP release by dispersed rat inner adrenocortical cells (maximal effective concentration, 10(-7) M). The effect of 10(-7) M galanin was blocked by 10(-6) M galantide, a specific antagonist of galanin receptors. Galanin (10(-7) M) also enhanced corticosterone and cyclic-AMP responses of dispersed cells to submaximal but not maximal (10(-9) M) effective concentrations of ACTH, and again this effect was reversed by galantide. The ACTH-receptor antagonist corticotropin-inhibiting peptide (10(-6) M) blocked corticosterone response of dispersed cells to 10(-9) M ACTH but not to 10(-7) M galanin; conversely, the specific protein kinase A inhibitor H-89 (10(-5) M) annulled the secretory response to both ACTH and galanin. In light of these findings, we conclude that galanin stimulates adrenal glucocorticoid secretion in rats, acting through specific receptors, coupled, like those of ACTH, with the adenylate cyclase/protein kinase A-dependent signaling pathway.
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