Atrial natriuretic factor administered to humans: 1984-1988

In initial studies of human atrial natriuretic factor (ANF) administered to man, 100 microns intravenous bolus doses infused in normal volunteers and patients with essential hypertension resulted in clear increases in urinary excretion of sodium (four- to sixfold), urine volume, calcium, magnesium, and phosphorous. In addition, in both groups an acute but short-lived fall in blood pressure and rise in heart rate was observed. In these studies and other high dose constant infusion experiments, the response of the renin-angiotension-aldosterone system and plasma catecholamines was varied, either remaining unchanged or showing stimulation when high doses of ANF caused acute and substantial falls in blood pressure. In contrast, constant low-dose infusions of ANF in both normal and hypertensive man (0.75-2 pmol/kg/min) have consistently shown clear suppression of plasma concentrations of renin, angiotensin II, and aldosterone by at least 50% of baseline values. Such "physiological" doses of ANF are not associated with sympathetic nervous system activation even though subtle but significant falls in blood pressure (particularly systolic) may occur.