Figure 2.

Effect of caffeine on contraction-stimulated 3-O-methyl-d-glucose (3MG) transport activity and Akt Ser⁴⁷³ phosphorylation in incubated rat skeletal muscle. Isolated epitrochlearis muscle was preincubated and incubated for 30 (A and C) or 120 (B and D) min in the absence (−) or presence (+) of 3 mmol/L caffeine. The muscle was tetanically contracted during the last 10 min of the incubation period and then subjected to the 3MG transport assay (A and B) or western blot analysis (C and D). Values are mean ± SE; n = 5–13 per group. *P < 0.05, **P < 0.01, ***P < 0.001 versus control; ^†P < 0.05, ^†††P < 0.001 versus contraction plus caffeine; NS, not significant.