Simultaneous determination of plasma aldosterone, corticosterone, 11-deoxycorticosterone, 18-hydroxydeoxycorticosterone, cortisol, and 11-deoxycortisol. Methods and applications.

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.