In vitro contractile activity of the mesotubarium superius from the rabbit oviduct in various endocrine states.
We investigated the influence of estrogen on the contractile activity of smooth muscle in the nonpregnant female reproductive tract, using as a model isolated strips of mesotubarium superius (MTS) removed from the rabbit oviduct. We studied four physiologic states in which muscular activity was influenced to varying degrees by endogenous estrogen. Normal estrous (estrogen dominated) rabbits were used as controls. We observed decreased activity in MTS from rabbits chronically deprived of estrogen (60) days postovariectomy). However, a dramatic increase in activity occurred in response to acute withdrawal of ovarian function (12 hours postovariectomy). An increase in activity also occurred at the time of ovulation. We concluded that acute withdrawal of endogenous estrogen is a potent stimulus to reproductive smooth muscle in the female rabbit and that it might contribute to increased muscular activity at ovulation.
D000818:Animals; D002369:Castration; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000502:physiology*; D004971:Estrus; D005187:Fallopian Tubes / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D007275:Injections, Intravenous; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000502:physiology; D010053:Ovary / Q000187:drug effects; D010060:Ovulation; D011247:Pregnancy; D011817:Rabbits; D013779:Tetrodotoxin / Q000008:administration & dosage / Q000494:pharmacology; D013997:Time Factors
D006063:Chorionic Gonadotropin; D004967:Estrogens; D013779:Tetrodotoxin; D004958:Estradiol