Effects of thermal stress and epinephrine on uterine blood flow in ewes.

Four muhiparous ovariectomized ewes, fitted with electromagnetic blood flow transducers around one mid-uterine artery, were utilized in two latin square design C.xperiments to evaluate interrelationships of thermal stress and epinephrine on an increase in uterine blood flow (UBF) induced by estradiol. Estradiol (20 /ag) was injected into the femoral vein and the subsequent induced increase in UBF was evaluated in response to thermal stress (21 vs 32 Ci Experiment I) and the interaction of thermal stress with epinephrine (Experiment 11). Thermal stress reduced the estradiol-induced increase in UBF (ml/min) by 37% and a combination of thermal stress plus epinephrine infusion (.20 /~g/kg body weight/min for 150 min) reduced UBF by 55%. Uterine blood flow is sensitive both to thermal stress ahd epinephrine. (