Fig. 4.
Caffeine reduced myotube diameter in by promoting the CaMKKβ/AMPK-dependent inhibition of mTORC1. Fully differentiated C2C12 myotubes were treated with either vehicle (control) or 5 mM caffeine for 6 h (n = 3). a Microscopy analysis revealed that caffeine and 1 μM rapamycin promoted a 15% reduction in myotube diameter, though the addition of caffeine plus rapamycin did not have an additive affect. b The decrease in skeletal myotube diameter that was partially attenuated by 10 mM 3-methyladenine (3MA, autophagy inhibitor) and completely inhibited by 30 μM STO609 (CaMKKβ inhibitor). (**P < 0.05)