Is There a Metabolic Program in the Skeletal Muscle of Obese Individuals?
Figure 2
Comparison of insulin signal transduction and fatty acid metabolism in human cultured skeletal muscle cells (HSkMC) from lean and severely obese individuals that were incubated in the presence or absence of free fatty acids for 16 hours. The values shown in the graphs were calculated from mean values in published papers. The values for muscle cells from lean individuals in the absence of fatty acids were used as 100%. (a) Insulin stimulated tyrosine phosphorylation of IRS-1 (Phos-IRS-1) [44]. (b) Insulin stimulated Akt phosporylation (Phos-Akt) [44]. (c) IRS-1 serine 312 phosphorylation (S312-IRS-1) [44]. (d) Complete fatty acid oxidation as determined from labeled CO2 production from 14C labeled palmitate (CO2) [43, 45]. (e) Incomplete fatty acid oxidation from calculating the 14C from labeled palmitate remaining in the acid soluble metabolite fraction divided by labeled CO2 production (ASM/CO2) [43, 45]. (f) Partitioning between lipid synthesis and fatty acid oxidation (synthesis/CO2) [25, 30, 43, 45].
