Effect of leucine supplementation on glucose and lipid metabolism in HepG2 cells. (A) 2-deoxy-D-[1,2-3H] glucose (2-DOG) consumption with or without the addition of insulin (1nM). Total intracellular glucose uptake was normalized to total protein content. (B) Levels of glucose secreted into the media with or without addition of insulin (1nM). (C) Total intracellular amount of triglyceride (TG), normalized to total protein content. (D) Glycogen content of homogenized samples treated with glucoamylase to hydrolyze glycogen into glucose. Glycogen amount was normalized to total protein content. Values are presented as mean ± SEM. Statistical significance relative to untreated control, *P <0.05, **P <0.01 (n =3).