CYPROTERONE-ACETATE DISPLACES OPIATE BINDING IN MOUSE-BRAIN

Drugs acting on androgen receptors modify opioid transmission in the c entral nervous system. To investigate a direct interaction, we studied whether the binding of [H-3]diprenorphine to mouse brain membranes wa s modified by cyproterone acetate (progesterone derivative with antian drogen activity), flutamide (non-steroidal antiandrogen), 5 alpha-dihy drotestosterone and progesterone. Only cyproterone acetate inhibited [ H-3]diprenorphine binding (IC50 = (1.62 +/- 0.33) x 10(-6) M) without modifying its association rate. These results suggest that cyproterone acetate binds to opiate receptors independently of its classical andr ogenic intracellular receptor effect.