Perforin-expressing granulated metrial gland cells in marine deciduoma

It has previously been shown that granulated metrial gland (GMG) cells of the pregnant uterus express abundant quantities of the lymphocyte pore-forming protein, perforin. No perforin was present before implantation of the embryo, but large numbers of perforin-producing GMG cells were observed after implantation, which coincides with decidualization of the uterus. The possible source of the activation factors responsible for perforin gene induction in GMG cells was studied here with the pseudopregnancy model, in which cervical stimulation of mice during estrus leads to a series of hormonal changes resembling those seen in pregnancy, but in the absence of an embryo. Subsequent stimulation of the uterus of pseudopregnant mice with oil causes the stimulated portion of the endometrium to differentiate into decidual tissue. Perforin-containing GMG cells were in fact present in the deciduomata, but not in adjacent nondecidualized tissues of the same mice. These results suggest that maternal factors associated with decidual tissue are responsible for the local expression of perforin in GMG cells.