Resistin and insulin resistance in hepatocytes: resistin disturbs glycogen metabolism at the protein level.

Resistin has been considered to link obesity with type 2 diabetes. Liver glycogen metabolism plays an essential role in maintaining glucose homeostasis, we investigated the effect of resistin on liver glycogen metabolism and attempted to identify its role in initiating insulin resistance and type 2 diabetes. Primary culture of rat hepatocytes was treated by resistin and insulin. Glycogen content was determined by the anthrone-reagent method. Real-time PCR, Western blot and enzymatic activity assay were used to detect key enzymes and genes involved in glucose metabolism. Hepatocytes exposed to resistin, but only in the presence of insulin, show a decrease in insulin-stimulated glycogen content. Decreased insulin receptor expression and GS activity and elevated GP activity was observed after the treatment of hepatocytes with resistin. No significant changes in the expression of the genes for these proteins were observed. These results strongly suggest that resistin effects glycogen metabolism at the protein level, and resistin is highly associated with insulin resistance and type 2 diabetes and is a candidate for the prevention and treatment of type 2 diabetes. Our results should lead to the development of novel strategies for the treatment of type 2 diabetes.