Effect of Glut4 siRNA knockdown on glucose uptake and Zfp407 expression. Differentiated 3T3-L1 adipocytes were electroporated with control or Glut4 siRNA. A, Glut4 or C, Zfp407 mRNA expression was determined by qPCR. B, four days post-electroporation, the cells were serum starved and treated with or without 100 nm insulin for 30 min. The rate of 2-DG uptake was determined. Results are the mean ± S.E., n = 3 per group. * indicates p < 0.05.