Expression Of GRP78 MRNA In Liver Of High-fat Diet Fed Rats

ObjectiveTo detect the expression of glucose regulating protein 78 (GRP78) mRNA in liver of high-fat diet fed rats, and investigate the relationship between endoplasmic reticulum stress and insulin resistance.MethodsInsulin resistance rat model was induced by high-fat diet feeding. Thirty male wistar rats were randomly divided in to two groups fed with either basic chow(NC, n=15) or high-fat diet(HF, n=15) for 10 weeks, then assessed by euglycemic-hyperinsulinemia clamp technique. The GRP78 mRNA expression was tested by Real Time PCR.ResultsThe glucose infusion rate(GIR) in HF group decreased significantly compared with that in NC group [GIR60-120 (0.90±0.15 vs 4.97±0.68) mg.kg-1.min-1, P<0.01].The GRP78 mRNA expression of liver in HF group was significantly increased in comparison with that in NC group (1.13±0.50 vs 0.43±0.10, P＜0.01). The GRP78 mRNA expression of liver was positively correlated with the percentage of visceral fat in body weight (r=0.52, P=0.019) and total cholesterol(TC) (r=0.51, P=0.022)ConclusionsThe expression of GRP78 mRNA increasing in liver of insulin resistant rats show that endoplasmic reticulum stress and unfolded protein response was provoked in liver of rats.