Effects of Long-term High-fat Diet on the Occurrence of Diabetes in Rats

Objective To investigate the effects of long-term high-fat diet and the modern lifestyle of more food and lack of exercise on insulin resistance and islet function. Methods 75 Wistar rats were feed by routine or high-fat diet for 11 months. Some of high-fat rats were induced to diabetic models by injecting 12mg/kg streptozotocin. Islet function was evaluated by intraperitoneal glucose tolerance test. Insulin sensitivity was detected by insulin tolerance test. Results Compared with control group, 2h blood glucose of high-fat group was elevated significantly. Fasting blood glucose of high-fat group was also elevated at eleventh month. Body weight of high-fat group was increased remarkably compared with control group, and the insulin sensitivity of high-fat group was decreased by 50% at forth month. Then insulin sensitivity of both groups was declined greatly. Hypoglycemic effect of 0.5 U/kg insulin at ninth month was similar to that of 0.1U/kg insulin at forth month. Furthermore, no significant difference of insulin sensitivity was observed between high-fat group and control. Conclusions Main course for insulin resistance is the modern lifestyle of more food and lack of exercise. The main effect of high-fat diet on the occurrence of diabetes is damaging islet function.