Polydatin improves glucose and lipid metabolism in experimental diabetes through activating the Akt signaling pathway

Recently, the effect of polydatin on lipid regulation has gained considerable attention. And previous study has demonstrated that polydatin has hypoglycemic effect on experimental diabetic rats. Repressed Ala pathway contributes to glucose and lipid disorders in diabetes. Thus, whether polydatin regulates glucose and lipid metabolism in experimental diabetic models through the Ala pathway arouses interest. The purpose was to explore the regulatory mechanism of polydain on glucose and lipid through Ala pathway. We used a diabetic rat model induced by high -fat and -sugar diet with low dose of slreprozocin and an insulin resisLani ElepG2 cell model induced by palmiLic acid Lo clarify the role of polyclaLin on glucose and lipid metabolism. Here, we found Lha L polydaLin significantly alienuaLed fasting blood -glucose, glycosylared hemoglobin, glycosylarecl serum proLcin, Loral cholesterol, Lriglycericle, and low-densiLy lipoprorein cholesierol iii diabetic rats. Furthermore, polyclaLin significanLly increased glucose uptake and consumption and decreased lipid accurnulaLion in insulin resisLanL HepG2 cells. PolyclaLin markedly increased serum insulin levels in cliabeLic raLs, and obviously acrivarecl the Ala signaling pathway in cliabeLic Ear livers and insulin resisLani HepG2 cells. PolydaLin markedly increased phosphorylated Gsic3 beta, decreased the protein levels of G6Pase and SREBP-lc, and increased protein levels of GCK, LDLR, and phosphorylated IRS in livers and HepG2 cells. Overall, the results indicate that polydatin regulates glucose and lipid metabolism in experimental diabetic models, the underlying mechanism is probably associated with regulating the Ala pathway. The effect of polydatin on increased Ala phosphorylation is independent of prompting insulin secretion, but dependent of increasing IRS phosphorylation. (C) 2014 Elsevier B.V. All rights reserved.