Concentrations of atrial natriuretic peptide in plasma and urine of kidney disease patients.

Concentrations of human atrial natriuretic peptide-like immunoreactivity (hANP-LI) were measured by a highly sensitive and specific radioimmunoassay (Biochem Biophys Res Commun 1986;137:231-6) in normal subjects and in renal disease patients without accompanying congestive heart failure, hypertension, edema, diabetes, or pregnancy. We attempted to clarify whether the hANP-LI concentration in plasma was increased by loss of renal mass. We found no correlation between the hANP-LI concentration in plasma and creatinine clearance (Ccr, 4.6-122.3 mL/min) in patients with renal disease (n = 63, r = -0.196), nor between hANP-LI concentrations in plasma and urine (n = 97, r = -0.207). The fractional excretion of hANP (FEhANP) correlated significantly with Ccr (n = 63, r = 0.520, P less than 0.01) and with FENa (n = 35, r = -0.503, P less than 0.01). Increased FEhANP in patients with chronic renal failure may have resulted because of an increase in single-nephron glomerular filtration rate similar to the FENa increase in these patients. The present data indicate that decreased renal function itself does not increase the concentration of hANP-LI in plasma.