Plasma levels of aldosterone, corticosterone, 11-deoxycorticosterone, progesterone, 17-hydroxyprogesterone, cortisol, and cortisone during infancy and childhood.

Plasma aldosterone (A), corticosterone (B), deoxycorticosterone (DOC), progesterone (P), 17-hydroxyprogesterone (17-OHP), cortisol (F), and cortisone (E) were measured simultaneously by specific radioimmunoassays in small plasma samples obtained from 174 normal infants and children between 2 hr and 15 yr of age. The significantly elevated neonatal mean levels (ng/ml) of 2.5 (A), 4.1 (DOC), 53.0 (P), and 6.6 (17-OHP) dropped significantly during infancy reaching prepubertal levels between 3 months and 3 yr of age, with a transient, significant DOC increase between 1--7 yr. The glucocorticoids F andB declined significantly from means of 68 and 4.4 to 11.4 and 0.28 ng/ml, respectively, during the first weeks of life, then increased significantly reaching adult levels between 1--3 yr of age. Mean E fell progressively from 74 ng/ml after birth to 10 ng/ml during 1--5 yr (P less than 0.0001), then slightly increased to adult levels. After age 7 yr, P and 17-OHP, in contrast to the other steroids, rose significantly in both boys and girls relative to pubertal development. The observed changes are thought to be due to (1) adaptation of the adrenal neocortex to extrauterine life after disruption of the fetoplacental unit, (2) a physiologic lack of corticosteroid binding globulin (CBG) during infancy due to maturation of hepatic CBG biosynthesis, (3) the functional immaturity of the infant kidney compensated by an increased activity of the renin-angiotensin-aldosterone system, and (4) gradually increasing gonadal secretion of progestins during puberty.