Prevention by vitamin A of the occurrence of permanent vaginal changes in neonatally estrogen-treated mice. An electron microscopic study.

Ovary-indepedent (estrogen-independent) irreversible proliferation and cornification on the vaginal epithelium in ovariectomized mice caused by neonatal injections of 20 microng estradiol-17 beta (E2) was suppressed by injections of 200 IU vitamin A acetate (VA) given simultaneously with E2. More than 2 months after the combined treatment were required for the suppression. A new type of cell of low electron density (Light cells) appeared at 40-120 days of age on the basal lamina of the vaginal epithelium in neonatally E2 plus VA-treated ovariectomized mice only at 50 days. Light cells contained small amounts of organelles. Columnar basal cells resembling those in normal estrous mice were also found in the E2 plus VA-treatedmice at 70-120 days. In one of the 120-day-old, E2 plus VA-treated mice, the epithelium consisted of only 2-3 layers of cells. Neither Light cells nor columnar cells were found in the atrophic epithelium.