Role of progesterone receptors during postpartum estrus in rats

►Intracellular progesterone receptors (PR) are essential in the display of postpartum estrus in rats. ►Serum estradiol and progesterone levels change throughout the first postpartum day. ►PR-A isoform is predominant in hypothalamus and preoptic area during postpartum. ►PR-B isoform expression increases at 9 and 12 h postpartum when there is a high display of sexual behavior.