Effects of metformin and thiazolidinediones on suppression of hepatic glucose production and stimulation of glucose uptake in type 2 diabetes: a systematic review.

Insulin resistance, which manifests itself as endogenous glucose overproduction and reduced insulin-mediated glucose uptake, is a core defect in type 2 diabetes. Metformin and the peroxisome proliferator-activated receptor-gamma agonists, the thiazolidinediones (TZDs), both lower glucose, although their mechanism of action is still subject to debate. This review analyses the evidence relevant to these mechanisms in vivo.