PROLONGED LOW-DOSE INFUSION OF ATRIAL NATRIURETIC FACTOR IN ESSENTIAL-HYPERTENSION

The C-terminal fragment of atrial natriuretic factor (ANF) was infused intravenously at 0.5 pmol/kg/min during 12 hours in 6 patients with mild to moderate essential hypertension, and in 6 normotensive volunteers, all recumbent and well hydrated, under a daily intake of 200 and 120 mmoles of sodium and potassium, respectively. Plasma C-terminal ANF tended to increase during ANF and to decrease during vehicle infusions. Plasma concentrations of the N-terminal fragment of ANF decreased by 20 to 40% (p < 0.05) during ANF and remained unchanged following vehicle infusion, suggesting that exogenous ANF reduces endogenous ANF secretion. ANF increased significantly plasma cyclic guanosine monophosphate (p < 0.01) from 3.1 ± 0.4 to 4.3 ± 0.8 and from 2.8 ± 0.4 to 5.1 ± 0.5 nmol/L in controls and patients respectively. ANF reduced systolic diastolic blood pressure during the last 8 hours of the infusion, by about 5% (p = 0.055) in patients, but did not alter blood pressure in controls. Sodium excretion during ANF increased 42% vs vehicle (p < 0.05), in the patients group and remained unchanged in controls. Hematocrit levels increased significantly in both groups with ANF infusion. We conclude that a prolonged infusion of ANF at a physiological rate causes a modest increase in plasma cyclic guanosine monophosphate, hemoconcentration, and reduces endogenous ANF secretion. It also stimulates diuresis and natriuresis and slightly reduces systolic blood pressure in patients with essential hypertension. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.