Galanin stimulates glucocorticoid secretion in rats through a receptor-dependent activation of the adenylate cyclase/protein kinase A-dependent signaling pathway.
Galanin, 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.
Mazzocchi
G
G
Department of Anatomy, University of Padua, Padova, Italy.
Rebuffat
P
P
Gottardo
G
G
Malendowicz
L K
LK
Nussdorfer
G G
GG
D000262:Adenylyl Cyclases / Q000187:drug effects*; D000302:Adrenal Cortex / Q000187:drug effects; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000187:drug effects*; D004789:Enzyme Activation; D019004:Galanin / Q000494:pharmacology*; D005938:Glucocorticoids / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011965:Receptors, Glucocorticoid / Q000187:drug effects*; D012636:Secretory Rate / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D013268:Stimulation, Chemical
D005938:Glucocorticoids; D011965:Receptors, Glucocorticoid; D019004:Galanin; D017868:Cyclic AMP-Dependent Protein Kinases; D000262:Adenylyl Cyclases