Measurement of 5-androsten-3beta,17beta-diol in spermatic and peripheral venous blood samples from the same human subjects by a radioimmunoassay method.

An original method for 5-androsten-3beta,17beta-diol (A-diol) measurement using an antiserum against A-diol-16-CMO-BSA is described. A-diol and testosterone (T) were determined by radioimmunoassay methods in spermatic and peripheral venous plasma of nine normal subjects during surgical intervention for inguinal hernia repair. In spermatic venous plasma the levels of T and A-diol were, respectively, 25.9 +/- 13.3 and 4.8 +/- 5.1 microgram/100ml (mean +/- SD) with an A-diol/T ratio of 0.19 +/- 0.15 (mean +/- SD); in peripheral plasma the levels of T and A-diol were, respectively, 269 +/- 58 and 91 +/- 25 ng/100 ml (mean +/- SD) with an A-diol/T ratio of 0.35 +/- 0.12 (mean +/- SD) significantly different from spermatic venous plasma (p less than 0.01). From these data a mean testicular A-diol secretion of about 0.70 mg/24 h can be calculated: this value corresponds approximately to the 50% of the blood production rate (BPR) of this steroid. So it can be assumed that a large amount of A-diol in systemic blood comes from sources outside the male gonad.