- Under oxidative stress, increased energy requirements are needed To induce repair mechanisms. As glucose is a major energy source in L6 myotubes, we evaluated glucose metabolism and transport, following exposure to glucose oxidase (H 2 O 2 generating system), or xanthine oxidase (O 2 · and H 2 O 2 generating system), added to the medium. Exposure for 24 h to 5 mM glucose and 50 mU/ml glucose oxidase, or to 50 μM xanthine and 20 mU/ml xanthine oxidase resulted in significant oxidant stress indicated by increased DNA binding activity of NF-κB. Under these conditions, approximately 2-fold increase in glucose consumption, lactate production and CO 2 release were observed. 2-deoxyglucose uptake into myotubes increased time and dose dependently, reaching a 2.6 ± 0.4-fold and 2.2 ± 0.7-fold after 24 h exposure to glucose oxidase and xanthine oxidase, respectively. Peroxidase prevented this effect, indicating the role of H 2 O 2 in mediating glucose uptake activation. The elevation in glucose uptake under oxidative stress was associated with increased expression of GLUT1 mRNA and protein. The observed 2-deoxyglucose uptake activation by oxidants was not limited to the L6 cell line and was observed in 3T3-L1 adipocytes as well.