Effect of rapamycin on p 70 S6 kinase phosphorylation status in C2C12 myotubes incubated with insulin and 1.0 × PC AA. Myotubes were serum starved overnight and next morning treated with rapamycin (2.2 × 10-8 M) in 1.0 × PC AA for 20 min. Half of the rapamycin treated or non treated cells were then stimulated with insulin (10-8 M) for another 20 min. A) immunodetection on western blot, B) respective densitometric analyses. Values are mean ± SEM from one experiment performed in duplicates.