Circulating renin in essential hypertension: an evaluation of its significance in the Japanese population.

Plasma renin activity (PRA) was measured in 139 healthy subjects and 200 patients with essential hypertension. There was an obvious relationship between the PRA levels and aging. Elevated PRA values were obtained only in younger subjects under 20 years of age, while the PRA levels were very low only in advanced ages over 60 years. In essential hypertensive subjects, subnormal resting PRA was found in 23.5 per cent, normal PRA in 64.5 per cent, and high PRA in 12 per cent. A marked impairment of renal function and severe retinal changes were observed in the patient with high resting PRA values. On the contrary, hypertensive complications of the kidney and ocular fundi were mild in the patients with low resting PRA values. A reaction of renin secretion was studied in 161 patients with essential hypertension. There were no apparent relationships between the responsiveness of the renin system to intravenous furosemide following upright posture and hypertensive vascular injury.