Simultaneous determination of testosterone, 5alpha-androstan-17beta-ol-3-one, 5alpha-androstane-3alpha,17beta-diol and 5alpha-androstane-3beta,17beta-diol in plasma of adult male rabbits by radioimmunoassay(1).

A simultaneous radioimmunoassay procedure for plasma testosterone (T), 5alpha-androstan-17beta-ol-3-one (DHT), 5alpha-androstane-3alpha,17beta-diol (3alphaol), and 5alpha-androstan-3beta,17beta-diol (3betaol) is described in this report. Peripheral plasma concentrations of T, DHT, 3alphaol, and 3betaol were 1.16 +/- 0.26, 0.49 +/- 0.15, 0.17 +/- 0.03, and 0.24 +/- 0.04 ng/ml, respectively, in adult male rabbits. In contrast, T, DHT, 3alphaol, and 3betaol peripheral plasma concentrations in dexamethasone-treated castrate rabbits were 0.07 +/- 0.01, 0.02 +/- 0.01, 0.07 +/- 0.01, and 0.05 +/- 0.01 ng/ml, respectively. These results represent the first simultaneous measurement of T, DHT, 3alphaol, and 3betaol in peripheral plasma of any male vertebrate. Moreover, we suggest that DHT, 3alphaol, and 3betaol represent the unidentified immunoreactive material found in peripheral plasma of male rabbits by Falvo and Nalbandov (1).