The structure and differentiation of granulated metrial gland cells of the pregnant mouse uterus.

A study was made with the light and electron microscopes of the granulated metrial gland cells of the decidua basalis of the pregnant mouse uterus, up to day 11 of pregnancy. The granulated metrial gland cells are large, up to 50 mu in diameter, mono- or binucleate and the glycogen rich cytoplasm typically contains many large glycoprotein granules which may be up to 5 mu in diameter. Morphological evidence is described in support of a lymphocyte-like cell being the precursor to the granulated metrial gland cell. This differentiation sequence is similar to that already proposed in the rat but differences between the ultrastructure of the mature metrial gland cells of rats and mice were noted.