Abstract

Introduction: Alterations in lipids metabolism are one of the important mechanisms for the treatment of insulin resistance and, hence for type 2 diabetes. On the other hand, PGC-1α, as a key regulator of mitochondrial biogenesis and function, by increasing)-oxidation of lipids plays an important role in improving insulin sensitivity. In the present study, the effects of Epigallocatechin- 3-Gallate (EGCG), an anti-obesity and enhancer of lipid catabolism agent, on PGC-1α protein expression was examined and compared with the anti-diabetic drug Rosiglitazone (RGZ). Materials and Methods: After differentiation of C2C12 myoblasts to myotubes, insulin resistance was induced by palmitate treatment. Afterward, PGC-1α protein expression was examined using the western blot method before and after treatment with insulin and after EGCG and RGZ treatment. Results: Palmitate treatment significantly decreased PGC-1 α protein expression in the C2C12 cells (P=0.001). Treatment of these cells with EGCG had no significant effect on the PGC-1α protein expression (P=0.67), whereas treatment with RGZ significantly increased expression of this gene at protein level (P=0.003). In addition, this significant increase in PGC-1α protein expression was maintained by simultaneous treatment with EGCG and RGZ (P=0.001). Conclusion: Our results showed that the effect of EGCG on PGC-1α protein expression was not significant, whereas RGZ significantly improved the palmitate-induced reduction of PGC-1α protein expression. Overall, it seems that anti-diabetic effect of EGCG is not exerted through its effect on the expression of PGC- 1α gene, in contrast to that of RGZ. © 2015, Endocrine Research Center. All rights reserved.