Intake of tea prevents postprandial hyperglycemia by promoting GLUT4 translocation in skeletal muscle

The anti-hyperglycemic effects of tea are well documented. However, the effects of tea on the translocation of glucose transporter 4 (GLUT4), the major glucose transporter for glucose uptake in the postprandial period, in skeletal muscle and the underlying molecular mechanisms are not fully understood. In this study, we investigated the translocation of GLUT4 and its related signaling pathways in skeletal muscle of animals given fermented tea. In long-term feeding experiment, green and black tea improved postprandial hyperglycemia by stimulating glucose uptake activity accompanied by the translocation of GLUT4 to the plasma membrane in muscle of high-fat diet-fed mice. In short-term feeding experiment, oolong, black and pu-erh tea activates both PI3K/Aktand AMPK-dependent signaling pathways to induce GLUT4 translocation, and increases the expression of insulin receptor to improve glucose intolerance. In conclusion, tea may prevent hyperglycemia and diabetes mellitus by promoting glucose uptake accompanying with GLUT4 translocation in muscle. Both PI3K/Aktand AMPK-dependent signaling pathways are involved in the tea-induced GLUT4 translocation.