The Determinants of Plasma-Renin Activity in Essential Hypertension

Abstract

Plasma renin activity was studied, under different conditions of stimulation, in normal subjects and patients with essential hypertension. In normal subjects, 3 components of renin release, basal, neural and Na-sensitive, could be delineated. Among the hypertensive patients, abnormal patterns of renin release were noted. The categorization of patients according to plasma-renin status, however, differed with the conditions of testing, being dependent both on the pathophysiology of the essential hypertension and the character of the renin-releasing stimulus, specifically whether this stimulus elevated plasma-renin activity through a predominantly neural (upright posture) or non-neural mechanism (dietary Na deprivation). Abnormal plasma renin activity in essential hypertension resulted in part from disordered sympathetic nervous system function. Patients with mild hypertension and elevated plasma renin activity exhibited increased neural stimulation of renin release, whereas in patients with low plasma-renin values, all 3 components of renin release, including the neural element, were diminished.