Cyproterone acetate prevents translocation of the androgen receptor in the rat prostate.

The translocation of the androgen receptor in prostatic tissue has been studied under the influence of different ligands (testosterone, methyltrienolone and cyproterone acetate) in vivo and in vitro. Nuclear and cytoplasmic androgen receptors were estimated using an exchange assay with [3H]methyltrienolone ( [3H]R1881) 1 h and 16 h after injection in castrated rats of either 100 micrograms testosterone (T), 10 mg cyproterone acetate (CA) or the combination of T and CA. Within 1 h after T administration, nuclear receptor levels increased with a concomitant depletion of cytosol receptors.