Atrial natriuretic peptide vascular receptor: regulation of low-affinity binding by calcium

Abstract
1. In the presence of calcium, both high- [dissociation equilibrium constant (Kd) 5.8 .times. 10-11 mol/l] and low-(Kd 1.2 .times. 10-8 mol/l) affinity binding of atrial natriuretic peptide was detected on plasma membranes prepared from sodium-depleted rats. 2. In contrast, under calcium-free conditions only high-affinity binding (Kd 6.9 .times. 10-11 mol/l) was detected. 3. The requirement for calcium for low-affinity binding suggests a different mechanism of action than that for the high-affinity receptor.