Ovarian Hormones Regulating Sexual and Social Behaviors in Female Prairie Voles, Microtus-Ochrogaster
In the induced ovulator, Microtus ochrogaster (the prairie vole), daily injections of estradiol benzoate (EB 0.5 ?g or 5.0 ?g) facilitated high levels of sexual receptivity in ovariectomized females withing 48 hr of the onset of treatment. A lower level of EB (0.05 ?g) with or without progesterone (0.5 mg) for five days did not induce lordosis. Four hr after sexually receptive EB-primed females received progesterone (0.5 mg) they either continued to show lordosis (EB 5.0 ?g group) or showed an inhibition of lordosis (EB 0.5 ?g group). Within 24 hr lordosis was markedly reduced in both groups. Progesterone-associated inhibitions were no longer apparent 48 hr after progesterone was discontinued. This general pattern of response to ovarian hormones is consistent with data described for other induced ovulators.