FOLLICULAR DEVELOPMENT AND OVULATION IN MACROPHAGE-COLONY-STIMULATINGFACTOR-DEFICIENT MICE HOMOZYGOUS FOR THE OSTEOPETROSIS (OP) MUTATION

To clarify the role of macrophages and macrophage colony-stimulating f actor (M-CSF) in follicular development and ovulation, the processes o f folliculogenesis and ovulation, numerical changes in macrophages, an d proliferative capacity of granulosa cells were examined in op/op mic e before or after daily M-CSF administration. The natural estrous cycl e was determined daily by means of vaginal smears. The number of ovula ted ova in both fallopian tubes was significantly smaller in op/op mic e than in normal littermates. Such ova markedly increased in number af ter daily M-CSF administration. The numbers of both antral and mature follicles in the proestrous ovary were markedly lower in op/op mice th an in the controls and increased after daily M-CSF administration. Fla sh-labeling with [H-3]thymidine showed that the proliferative capacity of granulosa cells in antral follicles was reduced in op/op mice but elevated after daily M-CSF administration. Numbers of granulosa cells and macrophages in the antral follicles were significantly decreased i n op/op mice but were increased after M-CSF treatment. All these data provide evidence that macrophages are implicated in the process of fol liculogenesis and ovulation.