Autoradiographic demonstration of estrogen receptors in the esophagus of baboons

Previous reports have indicated that certain sex steroids are intimately involved in the physiologic activities of the gastrointestinal tract. We performed autoradiographic studies using [³H]estradiol and [³H]dihydrotestosterone on male and female baboons for the purpose of identifying estrogen or androgen receptors, or both, in the lower and midregions of the esophagus. Discrete sites of localization of exposed photographic emulsion were observed over nuclei of skeletal muscle and interstitial cells of male baboons injected with the estrogen. No localization of receptors was observed in these same cells in females given estrogen nor in any males and females injected with the androgen. These observations suggest that skeletal muscle and interstitial cells of the male baboon contain specific highaffinity estrogen receptors that might have a direct effect on the skeletal muscle cells and may modulate their cellular activities.