Is hepatic glucose production increased in type 2 diabetes mellitus?

Based on recent studies, including our own, using what we consider to be an appropriate technique to estimate rates of hepatic glucose production (HGP), this article can be summarized as follows: 1) HGP in the overnight fasted state is near normal in obese type 2 diabetes (T2D) subjects, i.e., it may be increased by a mean of 12% compared to matched control subjects. 2) Suppression of HGP by insulin shows a rightward shift of the dose response curve (reduced insulin sensitivity) but normal maximal suppression (no maximum velocity defect). 3) In the overnight fasted state, gluconeogenesis is responsible for two thirds of HGP in T2D subjects and is about 5% to 10% increased compared to healthy subjects. 4) Suppression of HGP during a meal is close to normal. 5) The slightly increased HGP values throughout the 24-hour period together with reduced metabolic clearance rate (peripheral insulin resistance) and increased carbohydrate intake is responsible for the increase in fasting plasma glucose values. 6) Hypothetically, the role of the liver in nondiabetic and T2D subjects may be to produce the amount of glucose needed for metabolism in peripheral tissues. If insulin-mediated glucose uptake in skeletal muscle is reduced, plasma glucose will increase due to the "nonsuppressed" HGP values. Plasma glucose continues to rise until glucose-mediated glucose uptake compensates completely for the reduction in insulin-mediated glucose uptake.