Effect of prolonged infusion of ANF in normotensive and hypertensive monkeys

It is now recognized that bolus and short-term infusions of atrial natriuretic factor (ANF) into different species lead to a slight and transient decrease of blood pressure, while prolonged infusions cause a significant blood pressure reduction in hypertensive but not in normotensive rats. The present study was designed to evaluate the effects of prolonged ANF infusions on blood pressure and humoral parameters in normotensive and hypertensive African green monkeys (Cercopithecus aethiops). Human-ANF infusions (100 ng/kg.hr) in conscious, normotensive vervets for a period of 48 hours evoked highly significant decreases of blood pressure (from 124/65 to 104/53 mm Hg), plasma renin activity, aldosterone, and hematocrit. This fall in blood pressure was not accompanied by an increase of plasma cGMP levels at the end of the infusion. Forty-eight hours after the infusion was terminated, the decrease in blood pressure was still significant (97/46 mm Hg), as was the drop in aldosterone. In hypertensive monkeys, systolic blood pressure declined from 175 +/- 8 to 130 +/- 8 mm Hg, while diastolic pressure fell from 117 +/- 10 to 88 +/- 4 mm Hg. These data demonstrate that the chronic infusion of ANF in both normotensive and hypertensive vervets has more profound effects than does acute bolus administration, effects that persist for a prolonged period of time after discontinuation of the infusion.