Amino Acids Do Not Alter the Insulin-Induced Activation of the Insulin Signaling Pathway in Neonatal Pigs

Agus Suryawan, Pamela M.J. O'Connor, Scot Kimball, Jill A. Bush, Hanh V. Nguyen, Leonard "Jim" Jefferson, Teresa A. Davis

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Feeding stimulates protein synthesis in skeletal muscle and liver of neonates and this response can be reproduced in muscle by the infusion of insulin or amino acids and in liver by the infusion of amino acids, but not insulin. Activation of insulin signaling components leading to translation initiation is associated with the feeding-induced stimulation of muscle protein synthesis in neonates. In this study, we examined the individual roles of insulin and amino acids in the activation of insulin signaling components leading to translation initiation, specifically, the insulin receptor (IR), insulin receptor substrate 1 (IRS-1), phosphatidylinositol 3-kinase (PI 3-kinase), protein kinase B (PKB) and ribosomal protein S6. Insulin secretion was blocked by somatostatin in food-deprived, 7-d-old pigs (n = 8-12/group); insulin was infused to achieve plasma levels of ∼0, 17, 52, and 255 pmol/L (∼0, 2, 6, 30 μU/mL), and amino acids were clamped at food-deprived or fed levels. In skeletal muscle, insulin increased the activation of IR, IRS-1, PI 3-kinase, PKB and S6 and stimulated protein synthesis. In liver, insulin increased the activation of IR, IRS-1, PI 3-kinase, PKB and S6, but had no effect on protein synthesis. Raising amino acids from the food-deprived to the fed level did not alter the insulin-induced activation of IR, IRS-1, PI 3-kinase and PKB but increased S6 phosphorylation and protein synthesis in skeletal muscle and liver. The results suggest that the stimulation of protein synthesis in muscle by insulin involves activation of insulin signaling components, and the stimulation of protein synthesis in muscle and liver by amino acids occurs by mechanisms independent of the early steps of this pathway. Furthermore, amino acids do not alter the insulin-stimulated activation of early steps in the insulin signaling pathway.

Original languageEnglish (US)
Pages (from-to)24-30
Number of pages7
JournalJournal of Nutrition
Volume134
Issue number1
StatePublished - Jan 1 2004

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Swine
Insulin
Amino Acids
Phosphatidylinositol 3-Kinase
Insulin Receptor Substrate Proteins
Proto-Oncogene Proteins c-akt
Insulin Receptor
S 6
Liver
Skeletal Muscle
Proteins
Food
Muscles
Ribosomal Protein S6
Aminoacylation
Muscle Proteins
Somatostatin
Phosphorylation

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

Cite this

Suryawan, A., O'Connor, P. M. J., Kimball, S., Bush, J. A., Nguyen, H. V., Jefferson, L. J., & Davis, T. A. (2004). Amino Acids Do Not Alter the Insulin-Induced Activation of the Insulin Signaling Pathway in Neonatal Pigs. Journal of Nutrition, 134(1), 24-30.
Suryawan, Agus ; O'Connor, Pamela M.J. ; Kimball, Scot ; Bush, Jill A. ; Nguyen, Hanh V. ; Jefferson, Leonard "Jim" ; Davis, Teresa A. / Amino Acids Do Not Alter the Insulin-Induced Activation of the Insulin Signaling Pathway in Neonatal Pigs. In: Journal of Nutrition. 2004 ; Vol. 134, No. 1. pp. 24-30.
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Amino Acids Do Not Alter the Insulin-Induced Activation of the Insulin Signaling Pathway in Neonatal Pigs. / Suryawan, Agus; O'Connor, Pamela M.J.; Kimball, Scot; Bush, Jill A.; Nguyen, Hanh V.; Jefferson, Leonard "Jim"; Davis, Teresa A.

In: Journal of Nutrition, Vol. 134, No. 1, 01.01.2004, p. 24-30.

Research output: Contribution to journalArticle

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