Autoradiographic investigation of estrogen binding in cultured rat ovarian surface epithelial cells

Autoradiographic evidence presented that the cultured rat ovarian surface epithelium exhibits estrogen receptor-like activity. Two autoradiographic techniques were used; one involved live cells that were labeled and freeze-dried, and the other the labeling of ethanol-fixed cells. Autoradiograms were prepared by dipping cells grown on plastic cover slips in liquid nuclear track emulsion. Exposure times were 1 to 4 weeks. Experiments using a pulse-chase technique in live cells and steroid competition tests in fixed and live cells gave evidence for translocation of tritiated estradiol from cytoplasm to nucleus in live cells and for a component of estrogen-specific binding in live and fixed cells. The techniques presented here for the investigation of estrogen receptors in cultured cells require little tissue, are simple, and relatively quick. Reports based on biochemical analyses of tissue homogenates claim the presence of estrogen receptors in human ovarian carcinomas of surface epithelial origin and in rat ovarian surface epithelium. The results of this study add further evidence that the ovarian surface epithelium has estrogen receptor activity and should be considered an estrogen target tissue.