RENAL AND VASCULAR EFFECTS OF C-TYPE AND ATRIAL NATRIURETIC PEPTIDES IN HUMANS

C-type natriuretic peptide (CNP) may affect renal and vascular functio ns differently from atrial natriuretic peptide (ANP). The objective of this study was to compare the renal and vascular actions of CNP to th ose of ANP in normal men. CNP or ANP (0.005, 0.01, and 0.05 mu g.kg(-1 ).min(-1)) were given by infusion to eight healthy volunteers. CNP cau sed dose-dependent increases in natriuresis (U-Na) and in the fraction al excretion of sodium (FEN,) with no effect on diuresis (UV), renal p lasma flow, and glomerular filtration rate (GFR). Fraction of filtrati on (FF) increased only with the 0.05 mu g.kg(-1).min(-1) CNP dose. ANP caused larger increases in U-Na, FENa, and FF than CNP and also incre ased UV at 0.01 and 0.05 mu g.kg(-1).min(-1) and GFR at 0.05 mu g.kg(- 1).min(-1). Although the ANP and CNP infusions produced similar elevat ion in the respective peptides plasma levels, urinary and nephrogenous guanosine 3',5'-cyclic monophosphate increased less in response to CN P than to ANP. Blood pressure, forearm blood flow, plasma renin activi ty, and aldosterone remained unaffected during the peptides infusion. Plasma ANP increased slightly during CNP infusion. Our data indicate a higher threshold of renal response to CNP than to ANP. in contrast to ANP, CNP probably may not act as an endocrine factor in humans.