Mechanisms of insulin resistance in humans and possible links with inflammation.
Insulin resistance is a major player in the pathogenesis of the metabolic syndrome and type 2 diabetes, and yet, the mechanisms responsible for it remain poorly understood. Magnetic resonance spectroscopy studies in humans suggest that a defect in insulin-stimulated glucose transport in skeletal muscle is the primary metabolic abnormality in insulin-resistant type 2 diabetics. Fatty acids appear to cause this defect in glucose transport by inhibiting insulin-stimulated tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and IRS-1 associated phosphatidylinositol 3-kinase activity. A number of different metabolic abnormalities may increase intramyocellular/intrahepatic fatty acid metabolites; these include increased fat delivery to muscle/liver as a consequence of either excess energy intake or defects in adipocyte fat metabolism and acquired or inherited defects in mitochondrial fatty acid oxidation. Understanding the molecular/biochemical defects responsible for insulin resistance is beginning to unveil novel therapeutic targets for treatment of the metabolic syndrome and type 2 diabetes.
Savage
David B
DB
Department of Internal Medicine, Yale University School of Medicine, New Haven, Conn 06510, USA.
Petersen
Kitt F
KF
Shulman
Gerald I
GI
D000818:Animals; D005227:Fatty Acids / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000209:etiology*; D007333:Insulin Resistance / Q000502:physiology*; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D009765:Obesity / Q000150:complications / Q000503:physiopathology
D005227:Fatty Acids; D005947:Glucose