INS and Insulin resistance: While it is not clear to what extent impaired mitochondrial function is an underlying cause or a consequence of insulin resistance, it is striking that both life style interventions (i.e. exercise or calorie restriction) and pharmacological treatments (i.e. thiazolidinediones) that enhance oxidative metabolism are also effective in ameliorating whole body insulin sensitivity, an effect that has been associated with the capacity of such treatments to induce mitochondrial biogenesis [12], [13], [14], [15].