The influence of age on the number of non-atretic follicles classified based on follicular size in the rat ovary.

The age-related changes in the number of follicles classified according to size were investigated. The number of large follicles expected to ovulate spontaneously was not influenced by age, though the number of small follicles 250-549 microns in diameter, recovered by PMSG and hCG, was not constant. There was no relationship between the number of large follicles and small ones. This study suggests that the variation in ovum count after superovulation depending on age may be based on the variation in the number of small follicles.