Relationship of endocrine state to spontaneous motility of sheep myometrium in vitro.

I T is generally considered that uterine motility is high during the follicular phase of the estrous cycle and relatively low during the luteal phase, although motility during the luteal phase varies somewhat among studies. In sheep, neither the variation in spontaneous uterine motility during the estrous cycle nor the effects of exogenous ovarian hormones on this motility have been studied extensively. Most reports on the subject deal primarily with uterine activity in response to pharmacological agents, with ovarian status given secondary importance (Alexander, 1945; Ambache and Hammond, 1949), although Polovceva (1942) reported that uterine motility, studied in vivo, was greatest during estrus and lowest on the fourth or fifth day post estrus. The present study was conducted to determine the effect of the endocrine state and exogenous ovarian hormones on the spontaneous motility of sheep myometrium in vitro.