Adrenomedullin and calcitonin gene-related peptide (CGRP) interact with a common receptor of the CGRP1 subtype in the human adrenal zona glomerulosa

Frozen sections of normal adrenal glands, obtained from patients undergoing unilateral nephrectomy for kidney cancer, were labeled in vitro with human [I-125]ADM(1-52). Autoradiography showed the presence of abundant ADM bind ing sites in the zona glomerulosa (ZG) and the outermost portion of the zon a fasciculata, which were completely displaced by the addition of an excess of cold ADM(1-52). Calcitonin gene-related peptide (CGRP) and the non-sele ctive ligand of the CGRP-receptor subtypes 1 and 2 CGRP(8-37) eliminated [I -125]ADM(1-52) binding in the ZG, while the selective ligand of CGRP recept or subtype 2 [Cys(acm)(2.7)]-CGRP and CGRP(1-8) were ineffective. These fin dings confirm the presence of ADM binding sites in the human ZG, and provid e the first morphological evidence that ADM and CGRP interact with a common receptor of the CGRP1 subtype.