Atrial natriuretic peptide in plasma of volume-overloaded children with chronic renal failure.

The effect of volume changes on the plasma concentration of atrial natriuretic peptide (ANP) in children with chronic renal failure was investigated by the use of a specific and sensitive radioimmunoassay. Predialysis plasma ANP was significantly higher in children with end-stage renal disease than in healthy children and children with advanced renal failure without evidence of volume expansion. During haemodialysis plasma ANP decreased significantly and plasma renin activity rose slightly, whereas plasma arginine vasopressin and aldosterone did not change. Plasma ANP correlated positively with volume status (body weight gain during the interval between two haemodialysis sessions). An expanded extracellular fluid volume thus seems to be a major stimulus for the rise in ANP in children with end-stage renal disease. The findings suggest that ANP may be important in volume homoeostasis.