Simultaneous determination of plasma aldosterone, corticosterone, 11-deoxycorticosterone,...

A method for the simultaneous determination of aldosterone, corticosterone (B), 11-deoxycorticosterone (DOC), 18-hydroxy-11-deoxycorticosterone (18-OH-DOC), cortisol, and 11-deoxycortisol in a single 1-ml sample of plasma is described. The method is applicable to both man and experimental animal. After extraction and purification by thin-layer chromatography (TLC), aldosterone was determined by radioimmunoassay (RIA) employing antibodies to aldosterone: B, DOC, cortisol and 11-deoxycortisol were determined by RIA employing antibodies to corticosterone; 18-OH-DOC was obtained colorimetrically using the Porter-Silber reagent. Recoveries after extraction and chromatography were: aldosterone 71% +/- 9.4 SD; B 81% +/- 10.2; DOC 73% +/- 8.4; cortisol 65% +/- 7.2; 11-deoxycortisol 74% +/- 6.3 using labeled steroids; 18-OH-DOC 82% +/- 8.7 using inert steroid. The method has a high specificity and is reproducible and accurate.