Atrial natriuretic hormone effect on renal function and aldosterone secretion in sodium depletion

The effects of atrial natriuretic hormone (ANH) on aldosterone secretion and renal function have been well documented, but the physiological role of ANH is still unknown. To address this issue, eight normal men were infused for 4 h with low-dose (1.1 pmol.kg-1.min-1) human [Ser-Tyr28]ANH after 3 days of low-salt (LS) diet. The same subjects were also studied with placebo infusion on LS and high-salt (HS) diet. ANH infusion caused doubling of urine flow, a fourfold increase in urinary sodium excretion, and a slight increase in potassium excretion. Immunoreactive ANH levels increased from 3.1 +/- 0.5 to 21.0 +/- 1.9 pmol/l during ANH infusion. ANH infusion suppressed plasma renin activity (PRA) to one-third of the basal value, and plasma aldosterone was suppressed from 46.5 +/- 6.5 to 20.9 +/- 2.6 ng/dl. Low-dose ANH infusion caused a marked increase in urine flow and urinary sodium excretion and prominent suppression of PRA and plasma aldosterone in sodium-depleted subjects. These results suggest a physiological significance of ANH in regulation of kidney function and aldosterone secretion.