Granulated metrial gland cells in the uterus and labyrinthine placenta of inbred and outbred pregnancies in mice.

The sectional area of the labyrinthine placenta, the number of granulated metrial gland cells in the labyrinth and the number of granulated metrial gland cells in the decidua basalis + metrial gland were investigated in mice following inbred, randombred or outbred matings. The sectional area of the labyrinth in mice of the inbred LAC129 strain was greater after an outbred mating than after an inbred mating, but no such difference was detected in pregnant mice of the inbred CBA/Ca strain. However, significantly more granulated cells were found per unit area in the labyrinths of outbred pregnancies than in those of corresponding inbred pregnancies and more granulated cells were found in the decidua basalis + metrial gland of the outbred pregnancies in pregnant mice of both inbred strains. These results support the suggestion, made by previous workers, that granulated metrial gland cells are involved in the immunology of pregnancy. The number of granulated cells found in the labyrinthine placenta appears to be at its highest during the growth period of the labyrinth.