Sex steroid concentrations in plasma from the canine deferential vein

Sex steroid concentrations in plasma collected from the canine deferential vein were measured, after separation, by radioimmunoassay. The concentrations found were compared with those in the peripheral plasma. The mean concentrations of androstenedione, testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol and oestradiol-17 beta were 13.2, 14.7, 8.9, 4.6, 8.0 and 7.5 fold higher respectively in plasma from the deferential vein than in peripheral plasma. A close anatomical relationship was found between the vasa deferentia, the deferential vein and the peripheral plasma as well as between the deferential vein and the prostate gland. These findings emphasize and extend earlier conclusions that high levels of sex steroids present in the deferential vein could have a local influence on the growth of the prostate.