Objective To investigate the expression of hepatic glucose transporter-2 ( GLUT-2 ) and glu-cokinase(GCK)after gastric bypass(GBP)in type 2 diabetes mellitus(T2DM)GK rats and to discuss the mecha-nism of GBP improving insulin resistance .Methods 30 male GK rats aged 8 weeks were randomly divided into 3 groups:the operation group(10 rats), the sham operation group(10 rats)and the diet control group(10 rats), and 10 male SD rats aged 8 weeks were made as blank control group .The levels of fasting plasma glucose ( FPG) and fasting insulin(FINS)were measured and compared among the 4 groups before and 1,2 and 4 weeks after the operation and then the rats were sacrificed to retrieve the liver .The expressions of GLUT-2 and GCK mRNA and protein were detected by PT-PCR and Western blot respectively .Results As for GK operation group ,FPG levels at the 1st, 2nd,and 4th week after surgery ((11.06 ±0.52) mmol/L,(7.49 ±0.34) mmol/L,(5.20 ±0.08) mmol/L)respectively)were all lower than that before surgery (all P<0.05),and FINS level at the 4th week after surgery increased from(11.90 ±0.75)mmol/L to(14.20 ±1.23)mmol/L(P<0.05).The expressions of GLUT-2 and GCK mRNA and protein significantly increased in GK operation group 4 weeks after surgery ( P<0.01 ) . Conclusion The expressions of hepatic GLUT-2 and GCK in insulin signal transmission in T2DM rats are up-regu-lated after GBP , which enhance the signal transmission of insulin receptor , and improves the insulin sensibility .