INS and diabetes mellitus: Pioglitazone is a peroxisome proliferator-activated gamma (PPARγ) agonist that mediates the antidiabetic action via binding to nuclear PPARγ receptor.34 It regulates several genes related to glucose and lipid metabolism, which eventually increases insulin sensitivity.34 Our results show that most of the patients with DM who use pioglitazone have normal thyroid function, suggesting that this agent may have protective effects against thyroid dysfunction or at least is not associated with the development of any thyroid abnormalities.