Ovarian hormones are not necessary for postpartum regression of gap junctions.

We tested the hypothesis that gap junction degradation in myometrium after parturition in rats requires an ovarian hormone. Compared with unoperated or sham-operated controls, ovariectomy on day 21 slightly delayed parturition (nearly all animals delivered on day 23 instead of day 22). It also significantly reduced the number and membrane area occupied by gap junctions in delivering animals. However, it did not alter the disappearance of gap junctions which occurs less than 24 h after parturition or disassociate gap junction disappearance from parturition. These results do not support the hypothesis of a necessary role for ovaries in gap junctions degradation after parturition and suggest that events associated with parturition may initiate this event.