RESUMO
High-fat diet-induced insulin resistance rat model was assessed by euglycemic-hyperinsulinemic clamp technique.Compared with the control group,the vaspin mRNA expression in adipose tissue was significantly decreased in insulin resistant rats induced by high-fat diet( P＜0.05 ),which was increased by metformin( P＜0.05 ).These data indicate that metformin may ameliorate insulin resistance in rats via upregulating vaspin mRNA expression.
RESUMO
After 4 weeks old male Sprague-Dawley rats were fed with normal diet and high-fat diet for 10 weeks,the rats were treated with metformin (200 mg/kg) for 6 weeks. Insulin sensitivity was determined by hyperinsulinemic-euglycemic clamp technique.Realtime PCR and western blot were used to measure mRNA and protein levels of chemerin in perirenal adipose tissue of rats.The results showed that the expressions of chemerin mRNA and protein were higher in high-fat diet-induced insulin resistant rats compared with rats fed with normal diet ( both P＜0.05 ),and these incremental findings were diminished by metformin treatment ( both P＜0.01 ).The levels of chemerin mRNA and protein were correlated well with the epididymis fat mass index.
RESUMO
Fed with high-fat diet and assessed by hyperinsulinemia-euglycemia clamp technique, rat models with insulin resistance were successfully induced. Compared with normal chow group ( NC ), serum concentrations of free-fatty acids(FFAs) and baseline insulin in high-fat diet group(HF) was higher( P＜0.05 ), the average glucose infusion rate from 60 to 120 min( GIR60-120 ) was lower( P＜0.01 ), and the expression of p-IRE-lα in the liver was higher( P＜0.05 ). Furthermore, the expression of p-IRE-1α in the liver was positvely correlated with the serum concentration of FFAs. All these data indicate that high-fat diet may induce endoplasmic reticulum stress in the liver by elevating serum concentration of FFAs, and may participate in the genesis of insulin resistance via p-IRE-1α.
RESUMO
Objective To investigate the effect of swimming exercise on insulin sensitivity and interleukin-1 beta(IL-1β)mRNA expression in muscle tissue of insulin-resistant (IR) rats induced by high-fat diet.Methods The IR rat model was induced by high-fat diet feeding for 10 weeks and assessed by hyperinsulinemic-euglycemic clamp technique (HEC). The rats were divided into the fllowing three groups: normal group without exercise, IR groups with and without swimming exercise. After 4 weeks swimming excersie, insulin sensitivity and serum IL-1β levels were measured.Results Glucose infusion rate (GIR) of the IR rats was significantly elevated than that of non-exercise IR rats (P<0.01). Moreover, serum IL-1β levels were reduced markedly in IR rats (P<0.01). Conclusion High-fat diet feeding can partly reverse IR of rats to normal value. Swimming exercise improves insulin sensitivity and reduces the levels of IL-1β in IR rats induced by high-fat diet.