Renin, aldosterone and arterial pressure responses to acute beta-adrenergic receptor blockage in hypertensive patients.

The effect of acute (intravenous) beta-adrenergic blockade with propranolol or pindolol on arterial pressure (BP), plasma renin activity (PRA), and plasma concentration of aldosterone (PA) was evaluated in 20 essential hypertensive men. BP, PRA and PA were determined during continuous recumbency over-night (8 p.m. to 6 a.m.) every 30 min. Two groups of patients were observed. Patients of group 1 exhibited a characteristic day-night rhythm of PRA with low values before midnight and large increases early in the morning. Conversely, no rhythm and very low PRA values were observed in patients of group II. BP was higher in group II than in group I. In group I following intravenous propranolol or pindolol, BP fell within minutes and levels as well as rhythms of PRA were converted to those of group II without treatment. In group II day-night profiles of PRA and BP remained unchanged. Rhythm and concentration of PA in the two groups were not influenced by either drug. In 4 patients of group I infusion of angiotensin II inhibitor did not lower BP. The observations suggest that in the two groups dissimilarities in rhythms of PRA as well as in BP responses to beta-blockade may reflect differences in neuro-adrenergic tone.