Effect of Salt Depletion and Propranolol on Blood Pressure and Plasma Renin Activity in Various Forms of Hypertension

Geyskes, G. G. M.D.
Boer, P. Ph.D.
Vos, J. M.D.
Leenen, F. H. H. M.D.
Mees, E. J. Dorhout M.D.

Department of Nephrology, University Hospital, Utrecht, The Netherlands.

These investigations were made possible by a grant from the Netherlands Kidney Foundation (Nier Stichting Nederland).

Circulation Research 36(6):p I248-I256, June 1975.

The effect of propranolol therapy on the mean arterial pressure (MAP) and plasma renin activity (PRA) was studied in three groups of hypertensive patients who were also treated with saliuretics.

Group A: In 14 patients with essential hypertension on chlorthalidone treatment, an additional daily dose of 640 mg propranolol for two months led to a significant reduction of the MAP (from 124 to 105 mm Hg) and PRA (from 5.3 to 2.0 ng Al/ml/hr standing). There was no correlation between MAP reduction and either the original levels or change in PRA.

Group B: In 14 patients with essential hypertension and 5 with renal artery stenosis studied on a fixed salt intake, the plasma and extracellular volumes, PRA, and blood pressures were recorded before and after three days of diuretic induced salt depletion and, with maintenance of the depleted state, after three days of propranolol. Salt depletion resulted in a decrease in MAP from 132 to 128 mm Hg (NS), and PRA increased from 3.4 to 22.3 ng Al/ml/hr (P < 0.01). There was no correlation between change in MAP and PRA control values, PRA change, or any of the volume parameters. Addition of propranolol was followed by a rapid MAP decrease to 111 mm Hg (P < 0.01), and the PRA dropped to a mean of 8.5 (P < 0.01). No correlation was found between change in MAP and change in PRA. The patients with renal artery stenosis did not differ in their reactions from those with essential hypertension.

Group C: In five patients with moderate renal failure and normal to expanded ⁸²Br distribution volume, propranolol lowered MAP by 10% and lowered the PRA in all five. Salt depletion by furosemide to ⁸²Br volumes below normal resulted in a 10% decrease of MAP and a marked rise in PRA. In this state propranolol was followed by a further MAP reduction of 18% and a decrease in PRA. There was no quantitative relationship between MAP and PRA change during either of the treatment regimes.

It is concluded that in various forms of hypertension, the blood pressure can be effectively lowered by combining diuretics and propranolol regardless of the pretreatment PRA level.