The effects of the epidermal and fibroblast growth factors on the replicative lifespan of cultured bovine granulosa cells.

The effects of fibroblast growth factor (FGF) and epidermal growth factor (EGF) on the lifespan of cultured bovine granulosa cell cultures have been investigated. Granulosa cell cultures from small follicles (4-7 mm) had a lifespan of 11-12 generations, whereas the lifespan of cultures originating from large follicles did not exceed seven generations. The addition of either EGF or FGF to the medium of cultures originating from small follicles greatly increased the lifetime of the cultures, which can then exceed 60 generations. A similar, although less pronounced, effect was observed with cultures originating from large follicles. The lifespan of granulosa cell cultures depends upon the presence of FGF or EGF in the medium, as the deletion of the mitogens resulted in rapid terminal differentiation and a shortened replicative lifespan. As either FGF or EGF can prolong the replicative lifespan of granulosa cell cultures, it is suggested that limited replicative lifespan when maintained in the absence of mitogens is not so much determined by a fixed rate of mutation as it is by the culture conditions in which the cells are maintained.