The simultaneous assay of cortisol and 17alpha-hydroxyprogesterone in the plasma of patients with congenital adrenal hyperplasia.

Abstract

ABSTRACT The simultaneous determination of cortisol and 17α-hydroxyprogesterone (17-OHP) was carried out on a single plasma sample (0.6 ml) by the competitive protein-binding technique after a steroid partition by water and carbon tetrachloride. This procedure was tested for sensitivity, accuracy, reproducibility and specificity. It was then applied to plasma samples obtained from 20 control subjects and 28 patients with 21-hydroxylase deficiency. The cortisol value in the control group was 9.3 μg/100 ml ± 0.7 (se). This was moderately decreased in the untreated patients (group I): 6.7 μg/100 ml ± 0.9 (se), markedly decreased in those who discontinued treatment for 3 to 15 days (group II): 1.5 μg/100 ml ± 0.3 (se) and was suppressed in the treated patients (group III). In normal children, the 17-OHP level was at the limit of sensitivity of the method. It was increased to 29 μg/100 ml ± 2.8 (se) in group I and was unchanged in group II: 26.5 μg/100 ml ± 3.4 (se). The plasma 17-OHP remained elevated in the patients who received an oral cortisol dose ≦ 20 mg/m2/ day and decreased to ≦ 3 μg/100 ml in those who were treated with a cortisol dose > 20 μg/m2/day. A 17-OHP response to ® and a 17-OHP diurnal rhythm were were observed in the untreated patients. In contrast, the patients who had temporarily stopped their treatment had no reaction. A negative correlation between the cortisol and ACTH levels appeared in groups I and II (N = 19; r = –0.66; P < 0.01) and a positive correlation was noted between the 17-OHP and urinary pregnanetriol values in all the patients (N = 33; r = 0.52; P < 0.01). The reported technique described is simple and contributes to the diagnosis of congenital adrenal hyperplasia; it can also be useful in the follow-up of treated patients.