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Title: Developmental changes in insulin- and amino acid-induced mTOR signalling regulate muscle protein synthesis in neonatal pigs

Author
item DAVIS, TERESA - Children'S Nutrition Research Center (CNRC)
item SURYAWAN, AGUS - Children'S Nutrition Research Center (CNRC)
item FIOROTTO, MARTA - Children'S Nutrition Research Center (CNRC)
item ORELLANA, RENAN - Children'S Nutrition Research Center (CNRC)
item Burrin, Douglas - Doug

Submitted to: European Association of Animal Production Proceedings
Publication Type: Book / Chapter
Publication Acceptance Date: 5/10/2010
Publication Date: 9/6/2010
Citation: Davis, T.A., Suryawan, A., Fiorotto, M.L., Orellana, R.A., Burrin, D.G. 2010. Developmental changes in insulin- and amino acid-induced mTOR signalling regulate muscle protein synthesis in neonatal pigs. In: Crovetto, G.M. editor. Proceedings of the 3rd European Association of Animal Protection International Symposium on Energy and Protein Metabolism and Nutrition, Session 4: Systemic and local regulation mechanisms, an EAAP Publication, Wageningen Academic Publishers, The Netherlands, September 6-10, 2010, Parma, Italy, 127:249-250.

Interpretive Summary:

Technical Abstract: The enhanced efficiency, with which dietary protein is used for growth in the neonate, is due to the ability of neonatal muscle to markedly increase protein synthesis in response to feeding (Davis "et al.", 1996). The stimulation of protein synthesis by feeding in neonatal muscle is independently modulated by the post-prandial rise in insulin and amino acids (Davis "et al.", 2002; O'Connor "et al.", 2003). These responses decrease with development. We have previously demonstrated that feeding increases the activation of the insulin and amino acid signalling pathways leading to translation initiation in skeletal muscle of neonatal pigs and these responses decrease with development (Davis "et al.", 2000; Suryawan "et al.", 2001; Suryawan "et al.", 2006). Both insulin and amino acids increase protein synthesis in skeletal muscle of the neonatal pig, by increasing the activation of mammalian target of rapamycin (mTOR) and its downstream signalling proteins, ribosomal protein S6K1, and eukaryotic initiation factor binding protein 1, and promoting the binding of eIF4E to eIF4G. Insulin, but not amino acids, increases the activation of protein kinase B (Suryawan "et al.", 2007). All of these changes decrease with development (Davis and Fiorotto, 2009). To better understand the intracellular mechanisms involved in the postprandial stimulation of protein synthesis in skeletal muscle of neonates, we examined the independent effects of amino acids and insulin on the activation of potential mTOR regulators that had been recently identified in cell culture systems.