Reduced plasma renin activity in essential hypertension: effects of blood pressure, age and sodium.
ABSTRACT 1. Supine plasma renin activity and its responsiveness to erect posture and frusemide were reduced in fifty-one patients with essential hypertension, compared with fifty-one age- and sex-matched control subjects. 2. Twenty-four hour urinary sodium excretion was similar in hypertensive patients nad control subjects. 2. Twenty-four hour urinary sodium excretion was similar in hypertensive patients and control subjects, but after intravenous frusemide hypertensive patients excreted significantly less sodium. 3. A significant inverse relationship between plasma renin activity and diastolic blood pressure was demonstrated in hypertensive patients and in normotensive control subjects. 4. A significant inverse relationship between plasma renin activity and age, independent of blood pressure, was shown in hypertensive patients and control subjects. 5. It is concluded that the reduced renin values found in essential hypertension are, in part, the result of the elevated blood pressure acting on the kidney.
[show abstract] [hide abstract]
ABSTRACT: Intra-arterial pressure was recorded continuously in 26 patients with uncomplicated essential hypertension under standardized conditions. Recordings were analyzed beat by beat to obtain mean pressures and variability, expressed as the standard deviation of the frequency histogram. The major factors influencing variability were the level of pressure and the intensity of physical activity; systolic variability increased with progressive impairment of sino-aortic baroreflexes. Diastolic pressure increased with the level of sympathetic activity as reflected by plasma norepinephrine levels. After allowance for the decrease of plasma renin activity (PRA) with age, direct relationships were observed between PRA (log values) and the level of pressure and systolic variability; plasma angiotensin II values did not correlate. Systolic variability increased with the systolic response to cold but was unrelated to the response to dynamic or isometric exercise. Variability also tended to increase with obesity and was unrelated to age, sex, or race.Hypertension 2(3):333-41. · 6.21 Impact Factor