Insulin resistance in Zucker fatty or Abmole Company DAPT diabetic fatty rats has been associated with higher basal insulin secretion caused by increased fuel metabolism in pancreatic beta cells . The defects in pancreatic beta cell gene expression in Zucker diabetic fatty rats , but not in obese ZF rats who have normal glycemia , have been attributed to the development of diabetes. However, the insulin-regulated gene expression in hepatocytes from these insulin resistant animals has not been studied. Recently, in an attempt to understand how insulin induces transcription of its responsive gene, we identified insulin responsive elements in the Srebp-1c promoter as two liver X receptor binding sites and one sterol regulatory element . This suggests that insulin regulates the expression of its responsive genes after it stimulates the synthesis of endogenous agonists for nuclear receptor activation. It has been reported that the hepatic expression of Srebp-1c was elevated in liver of Zucker diabetic fatty rats . We hypothesize that insulin-regulated expression of genes involved in glucose and lipid metabolism may be altered in liver of insulin resistant animals. To focus on insulin resistance and obesity, but not diabetes, we analyzed insulin-regulated gene expression in hepatocytes from ZF rats, which have hyperlipidemia, but normal glycemia . Herein, we report the regulation of the mRNA levels of Srebp-1c and Pck1, two representative insulinregulated genes, in hepatocytes isolated from Zucker lean and ZF rats. For primary hepatocyte isolation, ZL or ZF rats in ad libitum or fasted overnight as indicated in the figure legends were euthanized with carbon dioxide. A catheter was inserted into portal vein and connected to a peristaltic pump with liver perfusion medium and liver digestive buffer . The inferior vena cava was cut open to allow the outflow of the media at flow rate of 10 ml/min. After completion of the digestion, livers were excised from the rat and put into a tissue culture plate containing liver digest buffer for removing connection tissues and allowing the release of hepatocytes. Medium containing hepatocytes were filtered through a cell strainer and spun at 50 g for 3 minutes. The cell pellets were washed twice with DMEM containing 5% fetal bovine serum, sodium penicillin, and streptomycin sulfate. After wash, the isolated hepatocytes were plated onto 60-mm collagen type I coated Gefitinib EGFR/HER2 inhibitor dishes and incubated in 4 ml of the same medium at 37uC and 5% CO2.