Metabolism of [14C]testosterone by human foetal and adult brain tissue.

The metabolism of [14C]testosterone in vitro by various areas of the human foetal brain has been studied and compared with that of adult brain. The predominant metabolites were 5alpha-dihydrotestosterone and 5alpha-androstane-3alpha, 17beta-diol, and also androstenedione, and all areas of the foetal brain showed similar activity. In the foetal pituitary gland, the activity of 5alpha-reductase was less prominent than that of 17beta-hydroxysteroid-dehydrogenase. Small quantities of oestradiol-17beta were produced from testosterone by the hypothalamus, temporal lobe and amygdala only, and no aromatization could be detected in the pituitary gland. 5alpha-Reductase activity was much lower in adult brain tissues and no oestradiol was identified in adult temporal lobe tissue.