THE MECHANISM OF ANTIANDROGENIC ACTION OF CHLORMADINONE ACETATE

We tried some animal experiments in order to elucidate the mechanism of antiandrogenic action, especially antiprostatic action of chlormadinone acetate (CMA). CMA inhibited the uptake of testosterone by the prostate. CMA itself was incorporated into the prostate cell selectively and inhibited the binding of cytosol 5α-DHT-recepter (The direct action of CMA at the prostatic cell level). CMA has both the direct and indirect actions on the prostate. The indirect action was mainly due to the acceleration of testosterone metabolic enzyme system in the liver and the inhibition of testosterone biosynthesis in the testis. The prostate of intact adult rat was slightly atrophied by the treatment of a small dose of CMA. On the other hand, the involution of rat prostate was intensified by the additive effect of the indirect action to the direct action of CMA, when a greater dose of CMA was administered to intact adult rats.The study on the changes in plasma hormone-contents and the biochemical finding of hypertrophic nodule suggested that improvement of dysuria of patients with BPH was mainly due to the direct effect of CMA.