Characterization of natriuretic peptide receptors in the rat parotid

Competition studies between 125I-ANP and ANP (atrial natriuretic peptide) or the ring-deleted analog C-ANF4-23 (C-ANF) revealed the presence of the A-type natriuretic peptide receptor (GC-A receptor) and the ANP-clearance (ANP-C) receptor in the rat parotid membrane. The ratio of the GC-A and ANP-C receptors was about 3 to 1. Enhancement of the cGMP level by the C-type natriuretic peptide (CNP) revealed the presence of the B-type natriuretic peptide receptor (GC-B receptor) in the rat parotid gland. Based on the binding studies with ANP and C-ANF and cGMP analysis by ANP and CNP, the natriuretic peptide receptors in the rat parotid gland were demonstrated to have a rank order on the amount of GC-A receptor > GC-B receptor > ANP-C receptor.