Phenethyl isothiocyanate suppresses protein degradation through the Akt pathway in the skeletal muscle of rats

Phenethyl isothiocyanate (PEITC) is an aromatic compound found in cruciferous vegetables. We previously have shown that it induces glucose utilization through Akt activation in mouse skeletal muscle cells, C2C12 myotubes. The Akt pathway regulates protein metabolism. However, the effects of PEITC on muscle protein metabolism remain unclear. This study investigated whether PEITC regulates the degradation of muscle protein in isolated rat skeletal muscles. Treatment with PEITC induced the phosphorylation of Akt in the rat extensor digitorum longus (EDL) muscles. PEITC suppressed the release of 3-methylhistidine (MeHis), a marker of protein degradation in the EDL muscles. Moreover, it tended to suppress the expression of atrogin-1, a muscle specific ubiquitin ligase. Akt inhibition diminished the suppressive effect of PEITC on MeHis release and atrogin-1 expression. These findings suggest that PEITC regulates muscle protein metabolism through Akt. PEITC may therefore serve as a dietary component with useful effects on skeletal muscle metabolism.