RADIOIMMUNOASSAY OF 3 DEOXYCORTICOIDS IN HUMAN PLASMA FOLLOWING HPLC SEPARATION

A radioimmunoassay of three deoxycorticoids, namely 11 beta,17 alpha-d ihydroxy-4-pregnene-3,20-dione (21-deoxycortisol), 17 alpha,21-dihydro xy-4-pregnene-3,20-dione (11-deoxycortisol), and 21-hydroxy-4-pregnene -3,20-dione (11-deoxycorticosterone) which are important for different ial diagnosis of congenital adrenal disorders, is described and evalua ted. Antisera against 3-(O-carboxymethyl)oximes conjugated to bovine s erum albumin were raised in rabbits. The radioligands were prepared by radioiodination of previously synthesized homologous tyrosine methyl ester derivatives. Following diethyl ether extraction, the steroids we re separated from each other and from cross-reactants by HPLC using a Nucleosil C8 reverse-phase column and a methanol-water mixture (7:5. v /v) as an eluent. Normal levels of analyzed steroids ranged from 0.02 to 0.348, 0.185 to 3.80, and 0.013 to 0.299 nmol/l, for 21-deoxycortis ol, 11-deoxycortisol and 11-deoxycorticosterone, respectively. The lev els of both deoxycortisols rose significantly after ACTH treatment. Da ta are given with respect to the concentrations of these steroids in s ome pathological situations such as 21-hydroxylase and 11 beta-hydroxy lase block, hyperaldosteronism, and polycystic ovary syndrome.