Androgen metabolism in the different lobes of the prostate gland of intact, gonadectomized or hypophysectomized rats with or without androgen substitution

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Abstract
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, 17 beta-hydroxy-5 alpha-androstane-3-one, 5 alpha-androstane-3 alpha, 17 beta-diol and 5 alpha-androstane-3 beta, 17 beta-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 5 alpha-reductase, NADP(H)-dependent 3 alpha-hydroxysteroid oxidoreductase (3 alpha-HSOR), NAD-dependent 3 alpha-HSOR, 3 beta-HSOR and 17 beta-HSOR, indicating that these enzymes are androgen dependent. The NADP dependent oxidation of 5 alpha-androstane-3 alpha, 17 beta-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 5 alpha-reductase activity which fell in spite of this treatment. Hypophysectomy or gonadectomy had different effects on the activity of several androgen metabolizing enzymes; 5 alpha-reductase activity in DP and CG, NAD(H) dependent 3 alpha-HSOR in VP and NADPH dependent 3 beta-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.