[Effect of various 1,3,5(10)-estratrien derivatives on the estrogen receptor transport into the nucleus in the guinea pig uterus].

The capacity of five derivates of 1, 3, 5 (10)-estratrien to be transported together with estradiol receptor from the cytoplasm into the nucleus in the uterus of sexually immature guinea pig was investigated. The extent of this transport was assessed by the amount of estrogen receptor in the nucleus following incubation of the uterine slices in the presence of the compound tested (2.5.10(-7) M). The content of estrogen receptor in the nucleus of the intact guinea pig uterus served as control. Incubation of the uterine slices with compounds containing 17 beta-hydroxyl group (2-brom-1, 3, 5 (10)-estratriendiol-3, 17 beta, 4-brom-1,3,5 (10)-estratriendiol, 3, 17 beta, 1, 3, 5 (10)-estratrienol-17 beta), led to a 1.9--4.2-fold increase in the content of nuclear estrogen receptor, this pointing to the transport of the estrogen receptor complex with these compounds into the nucleus. Two compounds (1, 3, 5 (10) estratrienol-3 beta and 3-methoxy-1, 3, 5 (10)-estratrien) contained no 17 beta-hydroxyl group and failed to increase the contents of the estrogen receptor in the nucleus in comparison with control. 17 beta-hydroxyl group is apparently necessary for the formation of conformative changes in the receptor molecule transforming the steroid-receptor complex into the active one, capable of transporting into the nucleus.