Restoration of muscle mitochondrial function and metabolic flexibility in type 2 diabetes by exercise training is paralleled by increased myocellular fat storage and improved insulin sensitivity.

Description

The purpose of this study was to investigate the effect of a well-controlled 12-week training program in type 2 diabetic patients and carefully matched obese healthy control subjects on insulin sensitivity, in vivo mitochondrial function and content, and intramyocellular lipid (IMCL) content. In order to conduct this study, 18 male type 2 diabetic subjects and 20 healthy male control subjects matched for body weight, body mass index, and age were included. The present study reported that exercise training in patients with type 2 diabetes completely restored mitochondrial function (measured in vivo) toward values observed in control subjects after training. The restoration of mitochondrial function was paralleled by improved insulin-stimulated glucose disposal and by complete restoration of metabolic flexibility and insulin-stimulated substrate oxidation toward control values even in the presence of increased IMCL storage. These findings suggest that the insulin-sensitizing effect of exercise training is not mediated by changes in body mass but generates beneficial effects in hepatic and adipose tissue insulin sensitivity.