Sterilization of Female Rats by Neonatal Placement of Estradiol Micropellets in Anterior Hypothalamus

Abstract

A pair of micropellets of a 1% or 10% estradiol (E₂)-paraffin mixture (containing 0.2 or 2μg E₂, respectively) or paraffin alone were implanted subcutaneously or intracerebrally in 5-day-old female rats. Animals given 10% E₂ pellets became sterilized regardless of loci of the pellets. Of those which had received 1% E₂ pellets, only animals with micropellets in the anterior hypothalamus became sterilized. It is suggested that neuronal components which are affected irreversibly by neonatal estrogen treatment are localized in the anterior hypothalamus.