Relationship between Plasma Aldosterone Concentration and Plasma Potassium in Patients with Essential Hypertension during Alprenolol Treatment

Plasma aldosterone concentration (PAC), plasma renin concentration (PRC), plasma potassium, plasma sodium and blood pressure (BP) have been measured in 22 patients with essential hypertension before and after treatment for one month with alprenolol. PAC, PRC and BP decreased and plasma potassium increased significantly during treatment. Plasma sodium, however, was unchanged. Changes in PAC were inversely correlated to changes in plasma potassium. No relationship could be demonstrated between PAC and plasma sodium. Mean BP was inversely correlated to PAC during alprenolol treatment, but bot before treatment. No relationship was found between changes in BP and changes in PRC. The results suggest that plasma potassium is an important regulatory factor for aldosterone secretion during alprenolol treatment. Other factors, however, must have a modulating influence and since the renin- angiotensin system is not suppressed to very low values, this system is possibly the most important of these factors. It is suggested that aldosterone secretion is not of primary importance in BP regulation during alprenolol treatment.