PLASMA PREGNENOLONE, PROGESTERONE, 17‐HYDROXYPROGESTERONE, TESTOSTERONE AND 5α‐DIHYDROTESTOSTERONE IN DIFFERENT TYPES OF CONGENITAL ADRENAL HYPERPLASIA

SUMMARY Unconjugated pregnenolone, progesterone, 17‐hydroxyprogesterone, testosterone and 5a‐dihydrotestosterone were simultaneously measured by radioimmunoassay in plasma from children with congenital adrenal hyperplasia (CAH) due to a deficiency of 21‐hydroxylase (21‐OHase), 11 β‐hydroxylase (11β‐OHase) or 3β‐hydroxysteroid dehydrogenase (3β‐HSD). These steroids were also measured in a reference group of children of similar age. The following concentrations of these five steroids were observed in the prepubertal children aged 0‐4‐10‐9 years: pregnenolone <0‐2‐0‐85 ng/ml; progesterone 0‐17‐0‐68 ng/ml; 17‐hydroxyprogesterone 0‐10‐0‐53 ng/ml; testosterone <0‐05‐0‐14 ng/ml, and 5α‐dihydrotestosterone <0‐05 ng/ml (detection limit of the method). The concentrations were clearly elevated in the plasma of children with CAH. A very high plasma concentration of 17‐hydroxyprogesterone differentiates a 21‐OHase deficiency from the two other types: children with this defect had levels mostly in excess of 100‐fold that of normal. Plasma progesterone concentrations in these patients were also high being in the range found during the luteal phase level in the adult. Their plasma testosterone concentrations showed a scatter from normal values to high adult male levels being mostly at the level of adult females. The concentrations of 5a‐dihydrotestosterone were at or above those of adult males. A high plasma concentration of pregnenolone with at most slightly elevated progesterone and 17‐hydroxyprogesterone levels differentiated the 3β‐HSD defect from the other two forms of CAH. The plasma profile of the five steroids determined in a patient with an 11 β‐OHase deficiency was close to normal, but slightly elevated pregnenolone, progesterone and 17‐hydroxyprogesterone levels were found to be characteristic of this enzyme deficiency.