Taken together, our data demonstrate that the dynamics of oxytocin receptor expression can be affected by stimulation with 17-beta-estradiol and oxytocin not only in the pregnant uterus, but also in the nonpregnant uterus. Therefore, dyscontractile phenomena of the nonpregnant myometrium also may be mediated via 17-beta-estradiol, oxytocin and the oxytocin receptor.