Protein and Amino Acid Supplementation Does Not Alter Proteolytic Gene Expression following Immobilization. Academic Article uri icon


  • Objective. To determine if supplementation of protein and amino acids (PAA) decreases skeletal muscle expression of atrophy-related genes, muscle mass, and strength during immobilization in humans. Methods. Twenty males wore a lower-limb immobilization boot for 28 days and consumed either a PAA supplement (28g protein) or carbohydrate placebo (28g maltodextrose), while consuming their normal daily diet. Testing sessions included dietary analysis, lower-leg girth and body composition measurements, strength testing, and gastrocnemius muscle biopsies. Muscle was analyzed for mRNA expression of markers in the ubiquitin and calpain systems, myostatin, TNF-, and NF-B. Results. All genes of interest increased over time (P < .05), but there was no difference between groups. Lower-leg girth decreased over time (P = 0.02); however, there were no significant changes in body composition or strength. Conclusion. Short-term lower-limb disuse, despite the absence of significant muscle atrophy, is associated with increases in skeletal muscle gene expression of several proteolysis-related genes. These changes do not appear to be altered by oral PAA supplementation.

published proceedings

  • J Nutr Metab

altmetric score

  • 0.5

author list (cited authors)

  • Bunn, J. A., Buford, T. W., Serra, M. C., Kreider, R. B., & Willoughby, D. S.

citation count

  • 8

complete list of authors

  • Bunn, Jennifer A||Buford, Thomas W||Serra, Monica C||Kreider, Richard B||Willoughby, Darryn S

publication date

  • December 2011