OBJECTIVETo explore the effect of puerarin injection on the amount of GLUT4 protein at the plasma membrane in insulin-resistant rat skeletal muscle.

METHODThe rat model of insulin resistance (IR) was made by being fed with high-fat diet. The animals were divided into three groups (ten in each group): group I: controls; group II: Insulin-resistant rats; group III: Insulin-resistant rats + Puerarin treatment. Insulin-resistant rats were injected with 100 mg puerarin injection per kg body weight through abdominal cavity once a day for 4 weeks. Fasting blood glucose and fasting serum insulin levels were measured before and after Puerarin treatment, respectively. Insulin treatment was achieved by intraperitoneal injection of insulin (1 unit insulin per kg body weight.) 15 minute before killing the animals. The right hindlimb skeletal muscle was rapidly dissected. Then the expression of GLUT4 protein at the plasma membrane in all the animals was assessed with Western blot method.

RESULTThe GLUT4 content at the plasma membrane in insulin-resistant rats skeletal muscle was significantly lower (about 31%) than that of controls (P < 0.01). Puerarin Injection partly corrected fasting blood glucose (from 6.17 +/- 0.67 mmol x L(-1) to 5.54 +/- 0.35 mmol x L(-1)) and fasting serum insulin levels (from 17.09 +/- 2.02 mU x L(-1) to 11.86 +/- 1.35 mU x L(-1)) and increased the GLUT4 content at the plasma membrane by 1.18-fold in insulin-resistant rats skeletal muscle.

CONCLUSIONPuerarin Injection can ameliorate IR, and the mechanism may be involved in increasing cell-surface level of GLUT4 through decreasing fasting blood glucose and fasting serum insulin levels, improving GLUT4 trafficking and intracellular insulin signaling.