Follicular growth and atresia in the mouse

Summary Follicles were classified on the basis of the number of layers of follicle cells, the presence and degree of development of the zona pellucida, and the presence of an antrum. Formation of an antrum in follicles with less than 7 to 8 cell layers and/or presence of necrotic cells was considered indicative of degeneration. When classified in this manner, the data suggest that follicles and their contained oocytes are committed to either normal development or atresia by the time a third layer of granulosa cells is formed. Presented in the formal symposium on Sexual Differentiation in Vitro and in vivo at the 29th Annual Meeting of the Tissue Culture Association, Denver, Colorado, June 4–8, 1978. This research was sponsored by the Division of Biomedical and Environmental Research, U.S. Department of Energy, under Contract W-7405-eng-26 with the Union Carbide Corporation.