Adrenomedullin stimulates steroid secretion by the isolated perfused rat adrenal gland in situ: comparison with calcitonin gene-related peptide effects.
Adrenomedullin (ADM), a vasodilatatory peptide contained in adrenal medulla, was found to induce a dose-dependent increase in aldosterone (ALDO) and corticosterone (B) release by the in situ perfused rat adrenal gland, along with a rise in the flow rate of the perfusion medium. The minimal effective dose for ALDO response was three and two orders of magnitude less than those able to evoke B and medium flow rate responses. Calcitonin gene-related peptide (CGRP), another vasodilatatory peptide contained in adrenal medulla and showing a slight homology in its amino acid sequence with ADM, elicited similar effects. CGRP (8-37), a specific antagonist of CGRP1 receptors, annulled all the effects of both ADM and CGRP, whereas l-alprenolol, a beta-adrenoceptor antagonist, partially reversed only ALDO response to the peptides. In light of these findings the following conclusions are drawn: i) ADM and CGRP stimulate rat adrenals in vivo to release B by raising blood flow rate; ii) ADM and CGRP enhance ALDO secretion via an indirect mechanism probably requiring the release of catecholamines by medullary chromaffin cells; and iii) the effects of ADM and CGRP on the rat adrenal gland are mediated by a common receptor of the CGRP1 subtype.
Mazzocchi
G
G
Department of Anatomy, University of Padua, Italy.
Musajo
F
F
Neri
G
G
Gottardo
G
G
Nussdorfer
G G
GG
D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism; D053607:Adrenomedullin; D000450:Aldosterone / Q000378:metabolism*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015740:Calcitonin Gene-Related Peptide / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology*; D003345:Corticosterone / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D010455:Peptides / Q000008:administration & dosage / Q000494:pharmacology*; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar
D000959:Antihypertensive Agents; D010455:Peptides; D053607:Adrenomedullin; D000450:Aldosterone; D015740:Calcitonin Gene-Related Peptide; D003345:Corticosterone