Effect of Baicalein on GLUT4 Translocation in Adipocytes of Diet-Induced Obese Mice.

BACKGROUND/AIMS: Although baicalein has been shown to increase insulin sensitivity in liver of mice, there is no literature available about the effect of baicalein on glucose transporter 4 (GLUT4) translocation from intracellular membrane pools to plasma membranes in adipocytes of diet-induced obese mice. METHODS: In the present study, the obese model was induced in mice fed a high fat diet (20% carbohydrates, 21% protein and 59% fat) for 16 weeks. The diet-induced obese mice were given 20mg/kg baicalein intraperitoneally (i.p.) once a day for 21 days. The plasma insulin was measured by enzyme-linked immunosorbent assay. Fasting blood glucose and insulin resistance indexes were measured by glucose tolerance test (GTT). The expression levels of PGC-1α, UCP1, GLUT4, PPARγ, pP38MAPK, pERK and pAKT in adipocytes were determined by quantitative real-time polymerase chain reaction and western blotting. RESULTS: The present findings showed that administration of baicalein decreased pP38MAPK, pERK and PPARγ levels, but enhanced pAKT, PGC-1α and UCP1 contents as well as GLUT4 expression in adipocytes, and reversed high fat diet-induced glucose intolerance, hyperglycemia and insulin resistance in diet-induced obese mice. Moreover, baicalein treatment increased GLUT4 concentration in plasma membranes of adipocytes, i.e. baicalein may prevent insulin resistance through the GLUT4 translocation from intracellular membrane compartments to plasma membranes in adipocytes. CONCLUSION: These results suggest that baicalein is a powerful and promising agent for treatment of obesity and insulin resistance via Akt/GLUT4 pathway.