17-Hydroxyprogesterone in the cosyntropin test: results in normal and hirsute women and in mild congenital adrenal hyperplasia.

The variations in plasma cortisol, testosterone and 17-hydroxyprogesterone (17-OHP) induced by an im injection of 0.25 mg cosyntrophin were studied in three groups of subjects: 16 healthy women, 16 hirsute women (HW) and 10 mild cases of congenital adrenal hyperplasia (CAH). The basal values of cortisol and testosterone were comparable between the three groups. In the patients with mild CAH, the mean 17-OHP concentration was increased: 483.9 ng/100 ml (113-1200 ng), but it should be noted that the individual values could overlap with the normal concentrations found in the controls and the HW during the luteal phase of the cycle. One hour after the injection of cosyntropin, a massive response of 17-OHP was observed in the mild cases of CAH, the mean basal concentration was multiplied by ten: 4843 ng/100 ml. The minimum concentration reached was 1740 ng/100 ml which is still 3-fold the highest level seen either in normal women (400 ng/ml) or in hirsute women (550 ng/100 ml). Determination of 17-OHP following a short-term ACTH stimulation, therefore provides evidence of partial 21-hydroxylase deficiency.