Human prepro atrial natriuretic factors 26-55, 56-92, and 104-123 increase renal guanylate cyclase activity

Human prepro atrial natriuretic factors 26-55, 56-92, and 104-123 as well as human atrial natriuretic factor (4-28) in the present investigation increased renal cortical and medullary cyclic GMP levels and maximally enhanced particulate Guanylate Cyclase activity [E.C. 4.6.1.2] two-fold in whole kidney homogenates, renal cortical and medullary membranes, and in isolated distal nephrons at their 1 microM concentrations. Dose-response relationships revealed that the half maximal [ED50] activation of Guanylate Cyclase was at their 10 nM concentrations in rat, rabbit, and dog kidneys. Both human atrial natriuretic factor and the prepro factors decreased Adenylate Cyclase activity. These results suggest that prepro factors 26-55, 56-92, 104-123 may also be functionally active.