Action of a novel nonsteroidal antiandrogen, AA560

The antiandrogenic properties of a new nonsteroidal antiandrogens, AA560 (N-2-chloromethyl-2-hydroxypropionyl)-3, 4, 5-trichloroaniline) were investigated. The ventral prostate, dorselateral prostate and coagulating gland weights in rats given AA560 at 1-9 mg/head were significantly less than those in the intact rats. The seminal vesicle weights in rats given 3-9 mg/head were significantly less than those of the intact group. In intact animals given daily 3 or 9 mg of AA560 there were significantly increases of serum FSH, LH and testosterone concentrations. In the in vivo experiment, the pretreatment with AA560 decreased the uptake of 3H-androgens in the nuclear fraction of the ventral prostate. On the other hand, a significant increase in the uptake of 3H-radioactivity in the cytosol fraction was observed. It was proved by the in vitro displacement study that AA560 inhibited the binding of 5 alpha-dihydrotestosterone with a receptor protein in the prostatic cytosol.