Presence of functional receptors for atrial natriuretic peptide in human pheochromocytoma

Pheochromocytoma, a catecholamine-secreting adrenomedullary tumor, has been shown to contain the functional receptor for human atrial natriuretic peptide(h-ANP). Release of catecholamines from tissue slices of pheochromocytoma was inhibited by h-ANP in a dose-dependent manner. Binding assays using 125I-ANP revealed a single class of high affinity binding sites for ANP. When covalently tagged with 125I-ANP and electrophoresed under non-reducing and reducing conditions, the receptor migrated as a 140-kDa band and a 70-kDa band, respectively, reflecting its disulfide-linked subunit structure. The presence of ANP receptor in pheochromocytoma was further demonstrated by immuno-histochemistry; the tumor was positively stained with an anti-receptor antiserum. The antiserum was also useful to establish the zona glomerulosa localization of ANP receptor in the normal human adrenal gland.