[Different reaction of plasma renin activity after propranolol in essential and renal hypertension]

In 16 normal subjects, in 29 patients with essential hypertension and in 25 patients with renal hypertension plasma renin activity was measured together with pulse rate and blood pressure under resting conditions and 15 minutes after the intravenous administration of 5 mg d-1-propranolol subsequently. Basal plasma renin activity (PRA) was correlated significantly to resting pulse rate in normal subjects and in patients with benign essential hypertension but not in patients with renal hypertension from chronic parenchymatous renal disease. In the normal subjects and in the patients with essential hypertension the decrease of not stimulated "basal" PRA 15 minutes after the administration of 5 mg d-1- propranolol was closely ralated to the initial plasma renin activity. In contrast, in the patients with well established renal hypertension the decrease of PRA was generally less pronounced or absent. Whereas in normal subjects as well as in patients with essentail hypertension in the sympathetic nervous system appears to be the major determinant for basal renin release, other factors, possibly the renal baroreceptors, may determine basal renin release in renal hypertension. This difference could possibley provide the basis for a simple biochemical test to differentiate between essential and renal hypertension.