Blockade by vitamin A of the occurrence of permanent vaginal changes in mice treated neonatally with 5alpha-dihydrotestosterone.

Estrogen-independent, persistent proliferation and cornification of the vaginal epithelium occurred in ovariectomized adult mice which had received neonatal injections of 50 microgram 5alpha-dihydrotestosterone (DHT). The occurrence of the permanent vaginal changes was prevented by injections of 200 IU vitamin A acetate (VA) given simultaneously with DHT. In 45% of the DHT plus VA-treated, ovariectomized mice, clear cells with pale cytoplasm appeared in the basal layer of the degenerating epithelium, while they came out in the epithelium of 13% of the ovariectomized mice receiving neonatal injections of DHT alone. For suppressing the permanent vaginal changes, including high mitotic rate, more than 1 month was required after the combined treatment. However, the occurrence of the permanent changes was not blocked by VA given after the DHT treatment. Permanent proliferation and squamous metaplasia took place in the uterine epithelium of the DHT-treated mice. Neonatal injections of VA also prevented the occurrence of the permanent uterine changes when given simultaneously with DHT but not when given after the androgen treatment.