The simultaneous assay of progesterone, 17-hydroxyprogesterone, and deoxycorticosterone in human plasma by competitive protein binding.

A method is described for the simultaneous measurement of prosterone (P), 17-hydroxyprogesterone (17-OHP) and deoxycorticosterone (DOC) in plasma by competitive protein-binding assay. After extraction, these steroids were purified by Sephadex LH-20 columns. The methods described here is sensitive enough to detect the above-mentioned steroids in as little as 5 ml of plasma under physiological conditions. The mean physiological plasma level (ng/100 ml) of P, 17-OHP and DOC are 18.2+/-1.6 (SE), 136.5+/-11.7, and 8.6+/-1.0 in men, 14.7+/-1.7, 61,2+/-3.6 and 6.0+/-1.2 in women in the follicular phase, and 645.0+/-108.1, 155.2+/-16.9, and 7.5+/-1.2, in the luteal phase of the menstrual cycle. By this method and others, the responses of plasma levels of 7 adrenal steroids (P, 17-OH, doc, corticosterone, deoxycortisol, cortisol and aldosterone) to ACTH infusion (25U i.v. over 8 hours) were investigated in healthy men. The increase of DOC was more pronounced than that of the other steroids.