Although insulin per se has been shown to stimulate whole- bodyproteinsynthesisinseveralmammalianspecies(Davisetal. 2002;O ’Connor et al. 2003), insulin sensitivity may also have a significantrole.Recentstudiesinneonatalpiglets(Bergeronetal. 2007) and steers (Gingras et al. 2007) have shown that protein anabolism is upregulated via enhanced insulin sensitivity in animals fed dietary long-chain n-3 polyunsaturated fatty acids. Inbothstudies,theincreaseinwhole-bodyproteinaccretionwas suggestedtobetheresultofadecreaseinproteinbreakdown,with no alteration in its synthesis. In addition, studies in rodents have shown an amino acid-enhanced sensitivity of skeletal muscle proteinsynthesistoinsulin,allowingformaximalratesofprotein synthesis to be achieved at lower insulin concentrations when amino acids are infused concurrently (Garlick and Grant 1988). Taken together, these above studies suggest a dynamic role for insulin, insulin sensitivity and amino acids and collectively they may act synergistically to stimulate protein synthesis.