FGF9 increases CCND1 mRNA and protein in bovine theca cells from large follicles. FGF9 increases CCND1 mRNA in granulosa cell from small and large follicles. IGF1 amplifies the FGF9-induced CCND1 mRNA in granulosa cells from small follicles. FGF9 likely uses the MEK pathway to increase CCND1 mRNA expression.