Intramyocellular lipid is associated with resistance to in vivo insulin actions on glucose uptake, antilipolysis, and early insulin signaling pathways in human skeletal muscle. Diabetes

To examine whether and how intramyocellular lipid (IMCL) content contributes to interindividual variation in insulin action, we studied 20 healthy men with no family history of type 2 diabetes. IMCL was measured as the resonance of intramyocellular CH2 protons in lipids/ resonance of CH3 protons of total creatine (IMCL/CrT), using proton magnetic resonance spectroscopy in vastus lateralis muscle. Whole-body insulin sensitivity was mea-sured using a 120-min euglycemic-hyperinsulinemic (in-sulin infusion rate 40 mU/m2 min) clamp. Muscle biopsies of the vastus lateralis muscle were taken before and 30 min after initiation of the insulin infusion to assess in-sulin signaling. The subjects were divided into groups with high IMCL (HiIMCL; 9.5 0.9 IMCL/CrT, n 10) and low IMCL (LoIMCL; 3.0 0.5 IMCL/CrT, n 10)