Abstract: Objective: To make clear the effects of estrog e n and dopamine on Pit-1 gene expression in rat pituitary Methods: Adult Wistar rats, ovariectomized, were divided into 3 groups at random Rats in E （n=5) and D （n=5) group were subscutaneously implanted with silastic tubes containing diethylstilbestrol（DES) Rats in C group （n=5) w ere implanted with blank silastic tubes Norprolac,dopamine type 2 receptor（D₂R) agonist, was orally administered to the rats in D group After 8 wee ks, Pituitary glands were weighed and collected for histopathological examination and immunohistochemistry observation The expression of Pit-1 mRNA in pituitaries were examined by RT-PCR Results: Pit-1 mRNA levels in group E were significantly greater than those in group C and group D （P＜0.001 and P＜0.05) Pit-1 mRNA levels were not obviously different betwe en group C and D Conclusion: Estrogen can stimulate the expre ssion of Pit-1 gene in rat pituitary While D₂R agonist can partly inhibit this stimulating effect