(A) C2C12 muscle cells pre-treated with Fluo-3, AM for 30 min were then treated with DBM (30 μM).

The green fluorescent signal was detected using confocal microscopy. (B) C2C12 cells pre-treated with STO-609, a CaMKK inhibitor, for 30 min and then treated with 30 μM DBM for 1 h. The cells were then lysed with lysis buffer, and the phosphorylation of AMPKα2 was assessed by western blot using phosphorylation-specific antibodies. The level of total AMPKα2 was also assessed as a control for protein loading. * p < 0.05, as compared with basal condition. (C) Myoblast L6 cells were differentiated for 7 days and then pre-treated with STO-609 (1 μM) and then DBM (30 μM) for 1 h. Glucose uptake was then assayed for 2-DG uptake as described in the Methods. *p < 0.05, compared with control. **p < 0.05, compared with DBM-treated cells.