Comparative Proteomics of Liver of the Diabetic Obese db/db and Non-Obese or Diabetic Mice

Type 2 diabetes mellitus is characterized by hyperglycemia and insulin resistance. Liver is a key organ for the maintenance of systemic glucose homeostasis in mammals, including humans and mice. Under many nutritional conditions the liver maintains nearly constant blood glucose. We analyzed the protein profile from the liver from ten-week old diabetic obese db/db mice through twodimensional electrophoresis (2DE) and the identity of differentially expressed proteins was determined by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). Some of these proteins were pyruvate carboxylase, carbamoyl-phosphate synthase, succinate dehydrogenase, ornithine aminotransferase, selenium-binding protein, proteasome subunit alpha type-2, regucalcin, creatine kinase M-type, and others, which are involved in metabolic process of carbohydrates, lipids and proteins. Results suggest that alteration in the expression of these proteins plays a role in the pathogenesis of obesity and diabetes. In addition, we identified some proteins that have not been previously associated with type 2 diabetes mellitus. Keywords: db/db mice, diabetes mellitus, liver, obesity, proteomics.