Androgen action blockade does not result in reduction in size but changes histology of the normal human prostate.

The effect of androgen blockade on the normal human prostate was studied in 16 healthy volunteers opting for male-to-female gender reassignment. Their ages ranged from 19 to 27 years. After 8 weeks of treatment with Anandron, serum hormone levels indicated anti-androgenic action and physical signs of feminization appeared. Prostate volumes (measured by ultrasound) before and following Anandron treatment remained the same. After 18 months of treatment with cyproterone-acetate and ethinyl estradiol, prostate volumes again were not changed. However, histology revealed glandular atrophy and an increase in stromal tissue. The significance of these findings is discussed.