A class of natural or synthetic hormones that binds to a cytoplasmic receptor and initiates translocation of the hormone-receptor complex to the nucleus of target cells of tissues rich in estrogen receptors, including the endometrium, myometrium, oviduct, vagina, fallopian tube, cervix, brain, liver, placenta, ovarian cells, Leydigs cells, kidney, prostate, pancreas, heart, and skin. (NCI) [ ]