PLASMA RENIN ACTIVITY AND ALDOSTERONE SECRETION IN CONGENITAL ADRENAL HYPERPLASIA

Abstract

Experiments were undertaken to study simultaneously plasma renin activity (PRA) and aldosterone secretion (Aldo-SR) in seven patients with congenital adrenal hyperplasia (CAH), aged 5 months to 12 years, and four normal subjects. Control values of renin on a liberal salt intake in 28 children were 19 ± 16 ng/l/minute, which is considerably higher than in adults (9 ± 7.6 ng/l/minute). Of the seven patients, four had PRA levels between 26 and 39 ng/l/minute. The other three had levels of 115, 249, and 1,250 ng/l/minute on a liberal salt intake. Aldo-SR was between 131 and 264 µg/24 hours in four subjects and was low in two (12 and 37 µg/24 hours). Salt restriction increased PRA 3.5 to five times in four patients, compared with two times in four normal subjects. Despite the high renin values, Aldo-SR increased at the utmost threefold, compared with a four- to eightfold increase in the normal children. That discrepancy between PRA and Aldo-SR points to a defect in aldosterone synthesis in all forms of CAH. PRA and Aldo-SR were both lowered by steroid therapy.