Electron microscopic observations on the elimination of the oocyte through the peritoneal epithelium in the neonatal mouse ovary.

Numerous ovarian oocytes of primordial follicles are lost postnatally by their elimination into the peritoneal cavity during days 1-6 in young mice. It is rarely found in animals over 2 weeks old. This phenomenon has been investigated by light and EM techniques. Oocytes that become extruded from the ovary this way appear to pass between the cells of the covering epithelium. The ultrastructural changes that take place during this process are described.