Rosiglitazone is a thiazolidinedione agonist of peroxisome proliferator-activated receptor γ (PPARγ) that binds to the ligand binding domain (LBD) of PPARγ with a Kd value of 43 nM. It selectively activates chimeras containing the LBDs of PPARγ over PPARα and PPARδ in a cell-based reporter assay when used at a concentration of 10 mM. Rosiglitazone also activates full-length PPARγ1 and PPARγ2 in a reporter assay (EC50s = 30 and 100 nM, respectively). It induces differentiation of C3H10T1/2 stem cells to adipocytes when used at a concentration of 1 μM. Rosiglitazone (4 mg/kg) decreases hemoglobin A1c (HbA1c) and fasting blood glucose levels in a rat model of type 2 diabetes induced by streptozotocin and a high-carbohydrate/high-fat diet. It also inhibits increases in contusion volume, macrophage infiltration and activation of microglia, and expression of IL-6, MCP1, ICAM1, caspase-3, and Bax in mouse cerebral cortex in a model of traumatic brain injury induced by controlled cortical impact when administered at a dose of 6 mg/kg. Formulations containing rosiglitazone have been used to improve glycemic control in the treatment of type 2 diabetes.