Heterologous enzyme immunoassay for serum androstenediol

A heterologous enzyme immunoassay for serum androstenediol (Adiol: 3 beta, 17 beta-dihydroxy- androst-5-ene) was established. The combination of anti- Adiol antiserum raised in rabbit against Adiol 7-O-(carboxymethyl)oxime (Ad iol 7-CMO) conjugated bovine serum albumin (Adiol 7-CMO-BSA) and Adiol 7-im inomethylcarboxylic acid conjugated alkaline phosphatase was used for the a ssay. The sensitivity of the heterologous assay system was superior to that of a homologous assay system in which an antibody raised in rabbit against Adiol 7-CMO-BSA and enzyme labeled antigen, Adiol 7-CMO conjugated alkalin e phosphatase, were used. The minimal amount of Adiol detected was 0.4 ng m l(-1) and the measurable range was from 0.4 to 150 ng ml(-1). Intra-assay c oefficients of variation (C.V.) were 8.6% (1.52+/-0.13 ng ml(-1), mean+/-S. D., n = 10) and 6.7% (13.4+/-0.9 ng ml(-1), n = 10). Inter-assay C.V. were 12.9% (1.63+/-0.21 ng ml(-1), n = 8) and 11.5% (12.2+/-1.4 ng ml(-1), n = 8 ). A linear relation was observed between the serum sample dilution and the Adiol concentration. For recovery study, authentic Adiol was added to seru m sample (original concentration: 1.43 ng ml(-1)). The calculated final Adi ol concentration was 2.99 ng ml(-1). The recovery was 98.6% (n = 5). The Ad iol concentrations in healthy subjects measured by the proposed assay (male : 1.1+/-0.3 ng ml(-1) (mean+/-S.D.), range: 0.7-1.7 ng ml(-1), age: 22-50, n = 10; female: 0.6+/-0.4 ng ml(-1), range: 0.2-1.6 ng ml(-1), age: 23-48, n = 20) were consistent with reported values. (C) 2000 Elsevier Science B.V . All rights reserved.