title: Stimulus summation and tachyphylaxis in estrogen response in sheep.
abstract: The response of the uterine circulation to estrogen has been extensively studied. Estrogen is the most potent vasodilator of the uterine bed. The magnitude of the vascular response depends on both the dose of estrogen used and the duration of exposure to estrogen. In this study, the relationship between the arterial concentration of estrogen, the duration and pattern of exposure, and the response was studied. This is a complex relationship, but one that is consistent with accepted models of estrogen-target tissue interaction. It was also shown that prolonged, high-concentration exposure results in tachyphylaxis.
mesh_terms: D000818:Animals; D001158:Arteries; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008954:Models, Biological; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep; D013618:Tachyphylaxis; D014599:Uterus / Q000098:blood supply*; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D004958:Estradiol