Effects of beta-adrenoreceptor blocking drugs on plasma volume. Renin and aldosterone as components of their antihypertensive action.

In young males with essential hypertension, propranolol and pindolol in small doses caused significant expansion of plasma volume (PV) after one month which did not prevent a reduction in BP. With higher doses, changes in PV were inconsistent and reductions in plasma renin activity (PRA) and 24-hour aldosterone excretion (AE) not closely related to BP changes. The effects of beta-adrenoreceptor blocking drugs on PV, PRA, and AE do not appear to be important components of their anti-hypertensive action.