Endometrial granulocytes of the pregnant hamster.

The appearance and distribution of endometrial granulocytes in the pregnant hamster were studied by light and electron microscopy. They first appeared in the tissue spaces of the mesometrial decidua and in the decidual sheaths of the spiral arteries. At the base of the mesometrial triangle they were restricted to the cellular sheaths of the arterial channels supplying the chorio-allantoic placenta and were not diffusely distributed throughout the mesometrial triangle. The endometrial granulocytes of the pregnant hamster uterus appear to be similar in structure and distribution to the granulated metrial gland cells of rats and mice and are not restricted, as previous literature suggests, to the walls of arterial channels.