Effects of cyproterone acetate (CPA) on pituitary gonadotrophin release and on androgen secretion before and after LH-RH double stimulation tests in men.

Effects of cyproterone acetate (CPA) on pituitary gonadotropin release and on androgen secretion before and after luteinizing hormone-releasing hormone (LHRH) double stimulation tests in 10 men are reported. 10 mg of CPA orally/day for 12 weeks resulted in reduced spermiograms and in a 70% decrease in testosterone a 50% decrease in dihydrotestosterone (DHT) a 30% decrease in LH and a 40% decrease in follicle stimulating hormone (FSH). 4 weeks after cessation of CPA intake all hormones had returned to the normal range whereas the recovery period for the speriogram took about 12 weeks. The episodic fluctuations in gonadotropin secretion were not affected but the spiking phenomenon of androgen secretion was abolished. Pituitary responses to LH-RH were reduced for LH and FSH. The gradual increase of T and DHT in the course of the LHRH double stimulation tests was also reduced. It is postulated that a direct effect takes place at the testicular level and concluded that the progestational/antigonadotropic action of CPA predominates over the antiandrogenic action.