Plasma levels of atrial natriuretic peptide (ANP), arginine vasopressin (AVP), 
renin activity (PRA), aldosterone (PA), catecholamines and urinary 
prostaglandins (PG), as well as renal function were measured in children in the 
edematous state of the nephrotic syndrome before and after infusion of human 
serum albumin. Before albumin infusion, plasma levels of AVP, PRA, PA and 
noradrenaline (NA) and urinary excretion of PGE2, PGE-Met, PGF2 alpha were 
elevated. The mean value of plasma ANP was in the normal range. Albumin infusion 
produced a 36% increase in the calculated plasma volume. It was associated with 
a fivefold rise in the plasma level of ANP (31.6 +/- 22.6 vs. 151.4 +/- 52 
fmol/ml mean, SD), and a significant fall in the levels of PRA, AVP, PA, and NA. 
Similarly, urinary concentration of PGE2, PGE-Met and PGF2 alpha fell. Urine 
flow, GFR, UNaV, FENa, and COsm increased significantly, while CH2O remained 
unchanged. The diuresis, natriuresis and GFR correlated with the level of plasma 
ANP, while urinary sodium excretion did not correlate with PA or NA levels. 
These findings suggest that ANP plays an important role in albumin induced 
natriuresis in children with nephrotic syndrome.