title: A circadian rhythm of mitotic activity in the uterine luminal epithelium of the rat: effect of estrogen.
abstract: The study was designed to determine whether or not the rat uterine luminal epithelium exhibits a mitotic circadian rhythm and to ascertain the effect of estrogen treatment at different time periods on the uterine epithelial mitotic response. Immature rats were injected with either sesame oil (controls) or 60 ng of estradiol-17 beta at eight time periods and were necropsied 24 hours after treatment. Colchicine was administered IP two hours before autopsy. Peak mitotic activity was observed during the nocturnal phase (0300) for both the control and estrogen-treated rats. The nadirs were recorded during the diumal phase (1800 and 1200 for the control and estrogen groups, respectively). The differences between low and high values were 1100% for the control rhythm and 101% for the estrogen animals. The data demonstrate the existence of overt circadian rhythms in the uterine epithelium for both control and estrogentreated rats.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D008938:Mitosis / Q000187:drug effects*; D051381:Rats / Q000033:anatomy & histology*; D013997:Time Factors; D014599:Uterus / Q000166:cytology* / Q000187:drug effects
chemical_list: D004967:Estrogens