Nature of induced persistent vaginal cornification in mice. I. Effect of neonatal treatment with various doses of steroids

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Abstract
Various doses of estradiol, testosterone, progesterone, or cholesterol were injected daily for five days, beginning within 24 hours after birth, into female RIII and BALB/c mice. Daily examination of vaginal smears of these animals revealed that neonatal administration of estradiol or testosterone, but not of progesterone or cholesterol, was effective in inducing persistent vaginal cornification. Mice of the RIII strain appeared to be more sensitive than BALB/c animals to the induction of persistent vaginal estrus by steroids. The existence of both ovary‐dependent and ovary‐independent types of persistent vaginal cornification was demonstrated. Ovariectomy completely eliminated vaginal estrus in most animals which had been treated neonatally with low doses of steroids. In contrast, neither ovariectomy nor combined ovariectomy + adrenalectomy + hypophysectomy had this effect in the majority of mice which had received higher dose levels of the same steroids neonatally. A single high dose of estradiol did not restore ovary‐dependent vaginal cornification in ovariectomized mice, and the administration of a high dose of progesterone for 15 days failed to block completely ovary‐independent vaginal cornification in mice of the BALB/c strain.