Testosterone metabolism in target tissues: Hypothalamic and pituitary tissues of the adult rat and human fetus, and the immature rat epiphysis

Abstract

Rat pituitary, hypothalamic and cerebral cortical minces are demonstrated to effect the conversion of testosterone (T) to 5α-androstan-17β-o1-3-one (DHT) and Δ 4-androstene-3,17-dione (Δ 4A). The pituitary effected the greatest conversion of T to both DHT and Δ 4A. The hypothalamus converted more T to DHT than did the cerebral cortex; but the conversion of T to Δ 4A in these two tissues occured to approximately the same extent. Analysis of the time course of the conversion of T to DHT in these tissues demonstrated the conversion to increase in a linear fashion over 180 min., while the maximum conversions in the hypothalamus and cerebral cortex were reached by 120 min. The conversion of T to DHT and Δ 4A was also demonstrated in the human fetal hypothalamus and pituitary, and in the distal femoral epiphysis of the growing rat. In the femoral epiphysis, 5α-androstane-3α,17β-diol was also identified.