Impact of 8-isoestrone analogs on estradiol binding in uterine tissue from ovariectomized rats

8-Isoanalogs of estrone were studied for their ability to influence estradiol binding in the cytosolic fraction of uterine tissue from ovariectomized rats and for their uterotropic activity 24 h after injection into such rats. Two groups of estrone 8-isoanalogs with opposite biological effects were identified: those increasing estradiol binding in the cytosolic fraction of uterine tissue and those decreasing this binding. Uterogenic activity was exhibited by all of the compounds tested, with the exception of compound I. No correlation was found between the uterogenic activity of the isoanalogs and hormone-receptor interactions.