Objective To detect the expression of adenovirus E2 promoter binding factor 1 ( E2F-1) and Pituitary tumor transforming gene ( PTTG) in rat prolactinoma and to explore their role in the development of prolactinoma． Methods 40 male Wistar( 120 ～ 150g) rats were randomly divided into two groups: experimental group ( E group，n = 20) : 17β- estradiol stuffed in silicone tube was subcutaneously implanted to induce rat prolactinoma model; the control group ( Cgroup，n = 20) blank silicone tube was subcutaneously implanted． After 10 weeks，all the rats were executed，blood was taken by cardiac puncture，4% paraformaldehyde was intracardially perfused and pituitary tissues were harvested，weighed．Serum PRL levels were detected by ELISA method; Pituitary tissue histopathological changes were observed; both expression of PTTG protein and E2F-1 protein were detected by immunohistochemistry SP method． Results Prolactinoma models were induced successfully as reflected by pituitary weight 、pituitary pathological change and serum PRL level． The expression of PTTG protein and E2F-1 protein in prolactinoma group was obviously higher than those in control group，( P ＜ 0. 01) and PTTG protein expression was positively correlated with E2F-1 protein( γ = 0. 764，P ＜ 0. 01) 。Conclusion PTTG and E2F-1 were co-overexpressed in prolactinoma，indicating their role in the development of prolactinoma．