Effect of haemodialysis on plasma concentrations of atrial natriuretic peptide in adult patients with chronic renal failure.

Twenty patients with chronic renal failure were studied before and after haemodialysis. Plasma atrial natriuretic peptide (ANP) concentrations were markedly elevated (P less than 0.01) before dialysis in comparison with healthy control subjects. After haemodialysis the plasma ANP concentration was lower in 19 patients (P less than 0.01) but remained above the normal range in all but three cases. Systolic and diastolic blood pressure and body weight fell during dialysis but none of these changes correlated with the reduction of the plasma ANP concentration. Chromatographic analysis of plasma extracts indicated that alpha-ANP is the predominant circulating molecular form. The increase in concentration of ANP in plasma between dialyses, at a time when many patients are susceptible to sodium and water overload, and its return towards normal after dialysis supports the putative role of ANP as a circulating factor released in response to sodium and water accumulation.