[Effect of chronic beta-adrenergic blockade on blood pressure and release of renin, aldosterone and cortisol in essential hypertension (author's transl)].

Blood pressure (BP), plasma renin activity (PRA) and plasma concentration of aldosterone (PA) and cortisol (PC) were determined in essential hypertensive patients before and after beta-adrenergic blockade with propranolol and prindolol. Serial measurements of PRA, PA and PC at 30 min intervals (8 p.m. to 6 a.m.) were performed in 8 patients. Administration of propranolol (50 mg three times daily) over a period of 4 weeks was followed by a significant reduction in BP, PRA and PA. PC remained unaltered. The pattern of rhythmic secretion of renin was abolished whereas that of aldosterone persisted at a lower level. Prindolol (10 mg three times daily) had a similar effect on BP as propranolol but failed to lower PRA and PA. Rhythmic secretion of renin was also markedly altered with prindolol in the absence of any change in rhythmicity of PA and PC. The hypotensive action of prindolol was not mediated via inhibition of renin release. The dissociation between PRA and PA rhythmicity indicates that during beta-adrenergic blockade diurnal rhythm of aldosterone secretion is not regulated by the renin-angiotensin-system. Rhythmicity of PC was normal, indicating that also ACTH-secretion was unaltered. Thus, under beta-blockade unchanged diurnal rhythm of aldosterone may be due to normal ACTH-secretion.