Z-350, a new chimera compound possessing α1-adrenoceptor antagonistic and steroid 5α-reductase inhibitory actions.

The effects of Z-350, (S)-4-[3-(4-{1-(4-methylphenyl)-3-[4-(2-methoxyphenyl)piperazine-1-yl]propoxy} benzoyl)indole-1-yl]butyric acid hydrochloride, a newly synthesized compound possessing α₁-adrenoceptor antagonistic and steroid 5α-reductase inhibitory actions, were studied in vitro. In functional experiments, Z-350 shifted the concentration/response curve for the phenylephrine-induced contraction of rabbit prostate, urethra and aorta to the right with pA₂ values of 8.04, 7.57 and 7.13, respectively. The binding affinity of Z-350 for α₁-adrenoceptors in rabbit prostate, urethra and aorta were estimated by the displacement of [³H]prazosin. The p K _i values for this action of Z-350 were 7.53, 7.95 and 7.62 for the prostate, urethra and aorta, respectively. α₁-Adrenoceptor subtype selectivities were studied in the submaxillary gland (α_1A) and liver (α_1B) of rat. Z-350 inhibited the specific binding of [³H]prazosin to α_1A and α_1B-adrenoceptors with p K _i values of 7.82 and 7.29, respectively. Z-350 inhibited rat prostatic steroid 5α-reductase non-competitively with a pIC₅₀ of 8.42. These results indicate that Z-350 is a α₁-adrenoceptor antagonist and is a steroid 5α-reductase inhibitor. It is expected that Z-350 will be a candidate drug for the treatment of benign prostatic hyperplasia. [ABSTRACT FROM AUTHOR]