Effect of proANF-(31-67) on sodium excretion in conscious monkeys

The purpose of this study was to determine the effect of proANF-(31-67) on renal function in conscious, chronically instrumented monkeys (Macaca fascicularis). The experimental protocol consisted of a 30-min control period followed by 60 min of peptide infusion and a 30-min recovery period. Atrial natriuretic factor (ANF)-(99-126), proANF-(31-67), or a combination of ANF- (99-126) plus proANF-(31-67) was infused at 15 pmol · kg^-1 · min^-1 . ANF-(99-126) caused sodium excretion to increase from 12.5 ± 3 to a peak of 37.9 ± 10.4 μeq/min, whereas fractional sodium excretion (FE(Na)) increased from 0.69 ± 0.2 to 2.3 ± 0.43%. ProANF-(31-67) increased sodium excretion from 12.7 ± 5 to a peak of 23.3 ± 9.0 μeq/min and FE(Na) from 0.56 ± 0.07 to a peak of 1.15 ± 0.4%. When ANF-(99-126) and proANF-(31-67) were infused in combination, sodium excretion increased from 9.6 ± 3 to a peak of 51.9 ± 12.5 μeq/min, whereas FE(Na) increased from 0.97 ± 0.4 to 3.9 ± 1.1%. Mean arterial pressure decreased by ~10 mmHg in all three groups. These findings indicate that intravenously administered pro-ANF-(31-67) causes an increase in sodium excretion and that when proANF-(31-67) and ANF-(99-126) are given in combination, they act in an additive fashion to increase renal sodium excretion.