Bovine adrenal medullary cells contain functional atrial natriuretic peptide receptors

The recent report that bovine adrenal chromaffin cells synthesized and secreted atrial natriuretic peptide, ANP, suggested that the peptide may have binding sites in the gland itself. Studies in bovine adrenal medulla membranes did reveal a single class of high affinity [125I]-ANP binding sites with a KD of 94 pM and a density of 1.7 pmol/mg protein. Binding was very rapid (association half-time: 2.5 min), and specific in that only unlabelled ANP displaced bound [125I]-ANP. Application of ANP to bovine chromaffin cells in culture, resulted in a concentration-dependent increase in cGMP synthesis. The data suggest the presence of biologically functional ANP receptors in adrenal chromaffin cells.