[Atrial natriuretic peptide in children with nephrotic syndrome].

The mechanism causing sodium retention in nephrotic syndrome remains controversial. There is an increasing evidence that sodium retention is directly due to an intrarenal mechanism. Atrial natriuretic peptide (ANP), realized from the heart during hypervolaemia, increases glomerular filtration rate, renal sodium and water elimination in both experimental animals and healthy men. In attempt to clarify the possible role of ANP in the mechanism of sodium retention in nephrotic syndrome we carried out this study. The purpose was: a) to determine plasma concentrations of ANP and values of creatinine clearance (CCr), natriuresis and diuresis both in basal conditions and after remission of the ilness, and b) to analyze the influence of acute hypervolaemia on ANP, Ccr, diuresis and natriuresis. A group of 12 children (aged 2-13 years) was studied during relapse and remission of nephrotic syndrome. In addition, 8 patients were studied during acute hypervolaemia due to intravenous infusion of 12% albumine. Twelve healthy children served as control group. Our results showed that in nephrotic syndrome group ANP was higher than in control group. Creatinine clearance, diuresis and natriuresis were significantly lower during relapse than in remission. The increase in Ccr, diuresis and natriuresis were observed during infusion of albumine, but no correlation was found between increased ANP and other parameters. This study showed that during relapse of nephrotic syndrome plasma concentrations of ANP are moderately elevated, but Ccr, diuresis nad natriuresis are blunted. We speculate that natriuretic and diuretic effects of ANP are impaired in children with nephrotic syndrome.