Effect of estrogen and anti-estrogen on reproductive function in neonatally androgenized female rats.

Abstract

Estradiol benzoate (EB) and ethamoxytriphetol (MER-25)2 were administered during puberty in an attempt to influence time of occurrence of the anovulatory syndrome and degree of receptivity in neonatally androgenized rats. When 5 days old, Sprague-Dawley female rats were injected with either oil or 3, 5, 10 or 50 tig testosterone propionate (TP) and, when 26 days old, with either 20 μg EB for 5 or 10 successive days or 5.0 mg MER-25 or oil for 10 days. All subjects were ovariectomized between 81 and 90 days of age and after 1 week received the first of 3 weekly receptivity tests with vigorous males. Heat was induced by injecting 10 μg EB followed 44 hr later by 0.5 mg progesterone. For the most part, the effect of EB and MER-25 on age of vaginal opening was independent of neonatal androgen treatment. EB advanced by approximately 5 days and MER-25 delayed by 6 days onset time of vaginal canalization. Age of onset of persistent vaginal estrus (PVE) was inversely related to neonatal TP dosage. EB increased by...