GCK and glucose metabolism disease: Peng et al. found that quercetin significantly enhanced the expression of phosphorylated glycogen synthase kinase 3β (GSK-3β), namely, Ser9, and Akt phosphorylation promoted the expression of glucokinase (GCK) protein (known as hexokinase type IV) in the liver of diabetic rats so as to enhance the synthesis of hepatic glycogen and alleviate the glucose metabolism disorders [64].