Atrial natriuretic peptide and sodium homeostasis in chronic renal failure

In order to evaluate the possible role of vasoactive hormones in the mechanism of exaggerated sodium loss due to reduced renal mass we measured plasma concentration of atrial natriuretic peptide (ANP), aldosterone, plasma renin activity (PRA), plasma noradrenaline, and dopamine, in 12 children with advanced chronic renal failure (mean CIn 17.8 +/- 2.6, mean +/- SEM, CPAH 93.5 +/- 17 ml/min per 1.73 m2, FENa 7.0 +/- 0.95%). No patient had clinical signs of volume overload. Plasma concentrations of ANP were not significantly different from those of healthy age-matched controls (29.2 +/- 7.2 vs 23.2 +/- 3.1 fmol/ml) and did not correlate with urinary sodium excretion. Plasma concentrations of aldosterone, PRA and noradrenaline, were also within the physiological range, while plasma dopamine levels were elevated (260 +/- 36 vs 98 +/- 11 pg/ml, less than 0.001). Our data do not support the notion that ANP or the renin-aldosterone axis play a major role in the adaptation of remaining nephrons to maintain long-term sodium balance in normotensive children with chronic renal failure.