17α-Hydroxyprogesterone (17α-OHP)

The steroid 17α−OH Progesterone is produced by the adrenal cortex and gonads. The 17α−OH Progesterone has little progestational activity, but it is of intense clinical interest because it is the immediate precursor to 11-desoxycortisol (Cpd-S). Cpd-S is produced by 21-hydroxylation of 17 OHP, measurement of 17aOHP is a useful indirect indicator of 21-hydroxlase activity. In congenital 21– hydroxylase deficiency, the most common variety of congenital adrenal hyperplasia (CAH), 17αOHP is secreted in abundant excess. Measurment of 17αOHP is therefore valuable in the initial diagnosis of CAH.