Amino acids and insulin act additively to regulate total proteolysis in C2C12 myotubes. Experimental procedures are the same as described under Figure 2. Values are means ± SEM for 5 different experiments performed in at least triplicates. * Indicates differences in protein degradation between 0.2 × PC AA (filled bars) & 1.0 × PC AA (open bars) treatments. ψ Represents differences between insulin versus control (without insulin) groups.