UTERINE MORPHOLOGY AND THE DISTRIBUTION OF GRANULATED METRIAL GLAND-CELLS IN THE VIRGIN AND PREGNANT SHORT-TAILED FIELD VOLE, MICROTUS-AGRESTIS

The morphology of the uterine wall in the virgin pregnant and postpart um short-tailed field vole (Microtus agrestis) was studied with partic ular reference to the distribution of granulated metrial gland (GMG) c ells. In comparison with the mouse, the changes which occur in the ute rine wall during pregnancy and into the postpartum period are broadly similar. However, unlike in the mouse, GMG cells were a feature of the uterine wall in virgin mice and of the antimesometrial decidua in pre gnancy. In pregnancy, GMG cells were not found in the lumina of blood vessels in the uterine wall or in the maternal blood spaces of the fet al placenta. During early pregnancy, giant interstitial trophoblast ce lls invade the decidualising endometrium. No association was found bet ween uterine leucocytes, including GMG cells, and interstitial trophob last cells, indicating that the trophoblast invasion is not influenced by leucocytes.