RESUMEN
Plasma levels of atrial natriuretic factor (ANF), and the effects of intravenously infused ANF (99-126) on renal filtration and blood pressure, were studied during different sodium intakes in six patients with uncomplicated diabetes mellitus. The change from a low (25 mmol/day) to a high (241 mmol/day) sodium intake was associated with a 2.5 fold increase in circulating immunoreactive ANF. On both sodium diets, an infusion of synthetic ANF (99-126) given at two different rates caused a progressive decrease of arterial pressure. On a low but not on a high sodium intake arterial hypotension occurred in two patients. Moreover, on a high sodium intake, ANF did not significantly modify glomerular filtration rate, the effective renal plasma flow and the plasma concentrations of renin and aldosterone. It increased the fractional excretion of sodium by 72%. On a low sodium intake ANF caused a progressive fall of glomerular filtration rates and effective renal plasma flow. It increased the fractional excretion of sodium by 100%, and increased plasma renin and aldosterone levels. In patients with uncomplicated diabetes mellitus, circulating ANF responds physiologically to variations in sodium intake. A low sodium diet could predispose to arterial hypotension and renal functional impairment during infusion of ANF (99-126).