EFFECTS OF OESTROGEN ANTAGONISTS ON MITOSIS AND [3H]OESTRADIOL BINDING IN THE MOUSE UTERUS

Abstract

SUMMARY Progesterone and megestrol acetate reduced oestrone-stimulated epithelial mitosis in the mouse uterus and increased it in the stroma. Neither progestin reduced the uptake of [3H]oestradiol by the uterus in vivo. Compounds ICI 46,474 and U11,100A were mitogenic in both luminal epithelium and stroma but did not antagonize the epithelial response to oestrone. U11,100A reduced the uptake of [3H]oestradiol by the uterus in a way similar to that shown by unlabelled oestradiol, but there was no evidence that ICI 46,474 competed for oestrogen receptors.