In Vitro and in Vivo Comparisons of Antiandrogenic Potencies of Two Histamine H2-Receptor Antagonists,Cimetidine and Etintidine-HCI

Abstract

The antiandrogenic potency of cimetidine was compared to that of a new histamine H2-receptor antagonist, etintidine-HCl (ORF 16753-02). Although both compounds displaced [³H]dihydrotestosterone from androgen receptors in vitro and inhibited androgen-stimulated growth of the accessory sex organs of male rats in vivo, etintidine-HCl was significantly less antiandrogenic than cimetidine in the analysis of androgen receptor binding and in the inhibition of seminal vesicle weights. Because etintidine-HCl has been shown previously to have more potent gastric antisecretory activity than cimetidine, its lower antiandrogenic activity suggests that etintidine-HCl has a much wider therapeutic ratio and that its use clinically will result in fewer antiandrogenic side effects.