The effect of cyproterone acetate on the plasma gonadotrophin response to gonadotrophin releasing hormone.

Cyporterone acetate (100-150 mg daily) was administered to 8 male patients with excessive libido. Within 3 months a significant fall (P less than 0.02) in plasma testosterone was demonstrated. The plasma luteinising hormone (LH) and follicle stimulatin hormone (FSH) responses to gonadotrophin releasing hormone (LH/FSH-RH) were also significantly impaired (P less than 0.05). A direct correlation between the resting plasma testosterone level and the LH response to LH/FSH-RH was demonstrated (r = 0.743). It is concluded that the fall inplasma testosterone levels in patients receiving cyproterone acetate may be attributed to suppression of LH release, rather than an antiandrogen effect on the testis or hypothalamus.