Flutamide. Mechanism of action of a new nonsteroidal antiandrogen.

Flutamide is a new nonsteroidal antiandrogen useful in the treatment of prostatic carcinoma. The mechanism of action of this compound was investigated using the sex accessory tissue of the male rat. Flutamide was found to block the action of both endogenous and exogenous testosterone and, in addition, to be a potent inhibitor of testosterone-stimulated prostatic DNA synthesis. Moreover, it is capable of inhibiting prostatic nuclear uptake of androgen. Electron microscopic observations further confirm the antiandrogenic properties of flutamide.