In conclusion, our study confirmed that chronic treatment of metformin, not only ameliorated insulin sensitivity but also regulated lipid metabolism in diabetic KKAy mice. Furthermore, metformin caused changes in the expression of many genes that involved in glucolipid metabolism, ER stress and cancer. These data provided molecular information for further exploration of the mechanisms involved in antidiabetic action of metformin. In addition to, our data may be significant in designing mechanism-based and targeted therapeutic strategies for diabetic mellitus, and lipid disorders. In future studies, we plan to validate the expression of these new genes found in this study in larger sample sizes.