Granulated metrial gland cells in the virgin and early pregnant mouse uterus.

A study has been made of the distribution of granulated metrial gland cells in the non-pregnant uterus, in the pre-implantation uterus and in the post-implantation interconceptual uterus of pregnant albino mice. Granulated cells were only rarely seen in the non-pregnant uterus. In the pre-implantation uterus, they were regularly seen after day 2 1/2 of pregnancy and were randomly distributed within the endometrium although there was considerable variation in numbers between animals. In interconceptual regions of the post-implantation uterus, granulated cells were found in the endometrium and, in each animal at day 5 of pregnancy, appeared to be present in smaller numbers in those regions more distant from the implantation sites. No granulated metrial gland cells were found in the interconceptual uterus at day 6 of pregnancy or later.