Effects of chronically administered atrial natriuretic factor in aldosterone-infused hypertensive rats

To assess the pathophysiological role of atrial natriuretic factors in mineralocorticoid hypertension, we studied the effects of chronic infusion of synthetic atrial natriuretic factor on blood pressure and sodium-water excretion in rats with aldosterone salt-induced hypertension. Administration of synthetic atrial natriuretic factor (150 micrograms/kg/day) to rats made hypertensive by 7-day infusion of aldosterone (100 micrograms/kg/day) and sodium loading with 1% NaCl as drinking water returned the blood pressure to control levels, and the antihypertensive effect was not associated with any changes in urine volume and urinary sodium excretion. These results indicate that atrial natriuretic factors may be involved in the regulation of blood pressure in mineralocorticoid hypertension, independent of the renal effects of these substances.