Glutamine Is a Key Regulator for Amino Acid-Controlled Cell Growth Through the mTOR Signaling Pathway in Rat Intestinal Epithelial Cells

Biochem Biophys Res Commun. 2005 Jan 7;326(1):174-80. doi: 10.1016/j.bbrc.2004.11.015.


Amino acids, especially branched-chain amino acids such as l-leucine, have been shown to regulate activation of p70 S6 kinase and phosphorylation of 4E-BP1 through the mTOR signaling pathway. In our recent study, l-arginine was also shown to activate the mTOR signaling pathway in rat intestinal epithelial cells. l-Glutamine is an amino acid that is required for culturing of numerous cell types, including rat intestinal epithelial cells. In this study, we showed that l-glutamine inhibited the activation of p70 S6 kinase and phosphorylation of 4E-BP1 induced by arginine or leucine in rat intestinal epithelial cells. Although the molecular mechanism of l-glutamine-induced inhibition of the mTOR signaling pathway is still unknown, the presence of this novel signal pathway may indicate that individual amino acids play specific roles for cellular proliferation and growth.

MeSH terms

  • Amino Acids / pharmacology
  • Animals
  • Arginine / pharmacology*
  • Cell Line
  • Cell Proliferation / drug effects
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation / drug effects
  • Glutamine / pharmacology*
  • Intestinal Mucosa / drug effects*
  • Intestinal Mucosa / physiology*
  • Leucine / pharmacology*
  • Protein Kinases / metabolism*
  • Rats
  • Ribosomal Protein S6 Kinases, 70-kDa / metabolism
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • TOR Serine-Threonine Kinases


  • Amino Acids
  • Glutamine
  • Arginine
  • Protein Kinases
  • TOR Serine-Threonine Kinases
  • mTOR protein, rat
  • Ribosomal Protein S6 Kinases, 70-kDa
  • Leucine