Abstract
Neonatal injections of 20μg 17β-estradiol (E2) induced persistent proliferation and cornification of the vaginal epithelium in adult ovariectomized C57 Black/Tw mice. However, permanent vaginal changes were prevented by various retinoids when, simultaneously with E2 treatment, the animals were given injections of 100μg daily dose of retinol, retinol acetate, retinal or of 200μg daily dose of retinol palmitate (RoP). Neonatal injections of a 100μg daily dose of RoP had no preventive effect on the occurrence of E2-induced permanent vaginal changes. This finding suggests that the preventive effect of RoP is weaker than that of other retinoids showing approximately the same degree of prevention. Combined treatment with E2 plus retinoic acid (even a small dose of 20μg) had such a toxic effect on newborn mice that they died within 7 days after birth, while the animals given neonatal injections of 20μg retinoic acid alone survived until the termination of the experiment.
