ANDROGEN METABOLISM IN THE DIFFERENT LOBES OF THE PROSTATE-GLAND OF INTACT, GONADECTOMIZED OR HYPOPHYSECTOMIZED RATS WITH OR WITHOUT ANDROGEN SUBSTITUTION

The effect of gonadectomy or hypophysectomy and the effect of substitution with testosterone, upon the reductive and oxidative metabolic transformations of testosterone, 4-androstene-3,17-dione, 17beta-hydroxy-5alpha-androstane-3-one, 5alpha-androstane-3alpha,17beta-diol and 5alpha-androstane-3beta,17beta-diol using NAD(H) and NADP(H) as added cofactors were examined in homogenates from the ventral, (VP), lateral (LP) and dorsal prostate (DP), and coagulating gland (CG) of adult Wistar rats. The fall in serum testosterone induced by gonadectomy or hypophysectomy led to reduced activity of 5alpha-reductase, NADP(H)-dependent 3alpha-hydroxysteroid oxidoreductase (3alpha-HSOR), NAD-dependent 3alpha-HSOR, 3beta-HSOR and 17beta-HSOR, indicating that these enzymes are androgen dependent. The NADP dependent oxidation of 5alpha-androstane-3alpha,17beta-diol in LP increased upon hypophysectomy and gonadectomy. Testosterone substitution of gonadectomized or hypophysectomized rats generally maintained enzymatic activity at the level of the control group, except for the 5alpha-reductase activity which fell in spite of this treatment. Hypophysectomy or gonadectomy had different effects on the activity of several androgen metabolizing enzymes; 5alpha-reductase activity in DP and CG, NAD(H) dependent 3alpha-HSOR in VP and NADPH dependent 3beta-HSOR activity in LP, DP and CG. There were marked differences between the rat prostatic lobes, both concerning the activity of the androgen metabolizing enzymes and the responses to the different treatment modalities.