Changes in TRIB3 mRNA levels (A) and TRIB3 protein levels (B) in L6 myotubes in response to different d-glucose media concentrations (0, 2.5, 5, 10, and 15 mM). mRNA was measured by real-time RT-PCR, while protein was analyzed by Western blotting and quantified by densitometry. Representative blot is shown, and data are means ± SE of 3 separate experiments. C: pAMPK protein levels in L6 myotubes in response to different d-glucose concentrations (0, 5, and 15 mM) and l-glucose (15 mM). Representative blot is shown, and data are means ± SE of 3 separate experiments. *P < 0.05.