Abstract: Objective To investigate the effect of Roux-en-Y gastric bypass surgery on renal gluconeogenesis in type 2 diabetes mellitus rats, and explore its possible hypoglycemic mechanism. Method Build diabetes mellitus animal models . Diabetic rats were divided into four groups randomly: control group , diabetes model group (DM group),sham Roux-en-Y gastric bypass group (SRYGB group), Roux-en-Y gastric bypass group (RYGB group). Plasma TG、TC and FFA were measured respectively before and 4th week after the operation in each group rats; the fasting insulin was measured and OGTT was taken before and 1st、2nd and 4th week after the operation, calculate the AUC of blood glucose concentration - time and ISI. The key enzymes of renal gluconeogenesis: G-6-P and PEPCK were detected using RT-PCR and Western blot respectively 4th week after the operation in each group rats. Results 4th week after surgery, RYGB group rats compare with DM and SRYGB group rats, Roux-en-Y gastric bypass surgery can reduce the level of blood lipid (P< 0.05),decrease the blood glucose of fasting and 2h after OGTT significantly (P<0.05), reduce the AUC (P<0.05), increase insulin sensitivity(P<0.05) ,decrease expression of G-6-P and PEPCK mRNA and protein in some degree. Conclusion: Roux-en-Y gastric bypass surgery can reduce blood glucose in diabetic rats significantly,improve the glucose tolerance, its mechanism may be related to decrease of G-6-P and PEPCK mRNA and protein levels in renal tissue，weaken renal gluconeogenesis.

Key words: gastric bypass surgery, Roux-en-Y, diabetes mellitus, kidney, gluconeogenesis