17-hydroxyprogesterone, androstenedione, and testosterone in normal children and in prepubertal patients with congenital adrenal hyperplasia

Abstract

To determine maximal plasma levels of androstenedione (A) and testosterone (T) which still can be considered non virilizing in 21-hydroxylase deficiency, we investigated plasma levels of these steroids in unaffected children and in adults. For T we found an upper limit of the prepubertal normal range of 16 ng/dl in girls and of 20 ng/dl in boys, with the exception of boys in the first half-year of life in which T is elevated up to the low adult range with peak values in the 2nd and 3rd month. During puberty T values show a significant difference between pubic hair stage 1 and stage 2. T levels below 20 ng/dl can be considered to be non virilizing. For A we found a plasma concentration of 86 ng/dl to be the upper normal level in both sexes before the onset of puberty. A values below this limit are expected to be non virilizing. To evaluate the usefulness of 17-hydroxyprogesterone (OHP) for the prediction of A and T and to define "acceptable" OHP levels in CAH we performed simultaneous determinations of OHP, T, and A in prepubertal patients treated for CAH. From these values we calculated the 95% confidence interval for prediction of T and A on known OHP levels. On an OHP value of 1.000 ng/dl, T can be expected to be between 6 and 60 ng/dl and A between 25 and 320 ng/dl. Because of these wide ranges, OHP has to be considered an unreliable parameter for predicting androgen levels in CAH.