AIM: To observe whether pancreatic and duodenal homeobox factor-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells in vitro.METHODS: Rat pancreatic tissue was submitted to digestion by collegenase, ductal epithelial cells were separated by density gradient centrifugation and then cultured in RPMI1640 medium with 10% fetal bovine serum. After 3-5 passages, the cells were incubated in a six-well plate for 24 h before transfection of recombination plasmid XIHbox8VP16. Lightcycler quantitative real-time RT-PCR was used to detect the expression of PDX-1 and insulin mRNA in pancreatic epithelial cells. The expression of PDX-1 and insulin protein was analyzed by Western blotting. Insulin secretion was detected by radioimmunoassay. Insulinproducing cells were detected by dithizone-staining.RESULTS: XIHbox8 mRNA was expressed in pancreatic ductal epithelial cells. PDX-1 and insulin mRNA as well as PDX-1 and insulin protein were significantly increased in the transfected group. The production and insulin secretion of insulin-producing cells differentiated from pancreatic ductal epithelial cells were higher than those of the untransfected cells in vitro with a significant difference (1.32 ± 0.43 vs 3.48 ± 0.81, P ＜ 0.01 at 5.6 mmol/L; 4.86 ± 1.15 vs 10.25 ± 1.32, P ＜ 0.01 at 16.7 mmol/L).CONCLUSION: PDX-1 can differentiate rat pancreatic ductal epithelial cells into insulin-producing cells in vitro.In vitro PDX-1 transfection is a valuable strategy for increasing the source of insulin-producing cells.