The relationships between serum concentrations of 17OH-progesterone and other serum and urinary steroids in patients with congenital adrenal hyperplasia.

Simultaneous determinations of serum concentrations of 17OH-progesterone, testosterone, androstenedione, and progesterone, and of urinary excretion of 17-ketosteroids and pregnanetriol have been performed at intervals in 31 patients with the C21-hydroxylase form of congenital adrenal hyperplasia. In prepubertal patients there were highly significant correlations between levels of 17OH-progesterone and those of testosterone, androstenedione, and progesterone, respectively. Similar correlations were observed in adolescent girls. In adolescent boys rising 17OH-progesterone levels were reflected by increasing levels of androstenedione and progesterone, but there was no change in serum testosterone concentrations. Levels of serum 17OH-progesterone below 200 ng/dl were uniformly associated with normal serum concentrations of testosterone, androstenedione, and progesterone, and normal urinary 17-ketosteroid and pregnanetriol excretion. In contrast, levels above 1000 ng/dl were accompanied by increased levels of the other steroids except in adolescent males; in this group the finding of unchanging serum testosterone concentrations in spite of rising 17OH-progesterone levels presumably indicates that testosterone of adrenal origin causes suppression of testicular testosterone production, either through a direct effect upon Leydig cells or via suppression of LH release.