Effects of uterine distension and oestradiol on cell kinetics in the endometrial epithelium of ovariectomized rats

Cell kinetics in the uterine epithelium of ovariectomized rats were studied after uterine distension and/or an estradiol injection, by cumulative 3H-TdR labeling and percentage of labeled mitoses (PLM). With both methods it was found that distension shortens the total cell cycle at the expense of G1 more than does estradiol. Both treatments act in a cumulative manner since the greatest reduction in T(C) is observed after distension plus estradiol. PLM curves showed that distension and/or estradiol induce a 30% reduction in S phase duration. The evolution of percentages of labeled cells and colchicine-blocked mitoses after these treatments confirms their additive effects and indicates that the mitogenic action of estradiol is delayed compared to that of distension. It is suggested that these factors stimulate epithelial cell division in the uterus through partly different metabolic channels.SCOPUS: ar.j