Pioglitazone-induced improvements in insulin sensitivity occur without concomitant changes in muscle mitochondrial function

These results suggest that 12 weeks of pioglitazone treatment improves insulin sensitivity, metabolic flexibility and myocellular lipid distribution without any effect on maximal ATP synthetic capacity in skeletal muscle. Consequently, pioglitazone-induced enhancements in insulin responsiveness and fuel utilization are independent of mitochondrial function.