Amino Acids

, Volume 37, Issue 1, pp 1–17 | Cite as

Amino acids: metabolism, functions, and nutrition

  • Guoyao WuEmail author
Review Article


Recent years have witnessed the discovery that amino acids (AA) are not only cell signaling molecules but are also regulators of gene expression and the protein phosphorylation cascade. Additionally, AA are key precursors for syntheses of hormones and low-molecular weight nitrogenous substances with each having enormous biological importance. Physiological concentrations of AA and their metabolites (e.g., nitric oxide, polyamines, glutathione, taurine, thyroid hormones, and serotonin) are required for the functions. However, elevated levels of AA and their products (e.g., ammonia, homocysteine, and asymmetric dimethylarginine) are pathogenic factors for neurological disorders, oxidative stress, and cardiovascular disease. Thus, an optimal balance among AA in the diet and circulation is crucial for whole body homeostasis. There is growing recognition that besides their role as building blocks of proteins and polypeptides, some AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. They are called functional AA, which include arginine, cysteine, glutamine, leucine, proline, and tryptophan. Dietary supplementation with one or a mixture of these AA may be beneficial for (1) ameliorating health problems at various stages of the life cycle (e.g., fetal growth restriction, neonatal morbidity and mortality, weaning-associated intestinal dysfunction and wasting syndrome, obesity, diabetes, cardiovascular disease, the metabolic syndrome, and infertility); (2) optimizing efficiency of metabolic transformations to enhance muscle growth, milk production, egg and meat quality and athletic performance, while preventing excess fat deposition and reducing adiposity. Thus, AA have important functions in both nutrition and health.


Amino acids Health Metabolism Nutrition 



Amino acids


Branched-chain amino acids


Nutritionally essential amino acids


Eukaryotic translation initiation factor


Mammalian target of rapamycin


Nutritionally non-essential amino acids


Nitric oxide


Portal-drained viscera



This work was supported, in part, by grants from National Institutes of Health (1R21 HD049449), National Research Initiative Competitive Grants (2008-35206-18764, 2008-35206-18762, and 2008-35203-19120) from the USDA Cooperative State Research, Education, and Extension Service, American Heart Association (#0755024Y), and Texas AgriLife Research (H-8200). The author thanks graduate students, postdoctoral fellows, technicians, and colleagues for their important contributions to the work described in this article.


  1. Baker DH (2008) Advances in protein-amino acid nutrition of poultry. Amino Acids. doi: 10.1007/s00726-008-0198-3
  2. Ban H, Shigemitsu K, Yamatsuji T et al (2004) Arginine and leucine regulate p70 S6 kinase and 4E-BP1 in intestinal epithelial cells. Int J Mol Med 13:537–543PubMedGoogle Scholar
  3. Blachier F, Mariotti F, Huneau JF, Tomé D (2007) Effects of amino acid-derived luminal metabolites on the colonic epithelium and physiopathological consequences. Amino Acids 33:547–562PubMedCrossRefGoogle Scholar
  4. Brasse-Lagnel C, Fairand A, Lavoinne A, Husson A (2003) Glutamine stimulates argininosuccinate synthetase gene expression through O-glycosylation of Sp1 in Caco-2 cells. J Biol Chem 278:52504–52510PubMedCrossRefGoogle Scholar
  5. Bronte V, Zanovello P (2005) Regulation of immune responses by l-arginine metabolism. Nat Rev Immunol 5:641–654PubMedCrossRefGoogle Scholar
  6. Brosnan JT (2001) Amino acids, then and now—a reflection on Sir Hans Kreb’s contribution to nitrogen metabolism. IUBMB Life 52:265–270PubMedCrossRefGoogle Scholar
  7. Chen LX, Yin YL, Jobgen WS et al (2007) In vitro oxidation of essential amino acids by intestinal mucosal cells of growing pigs. Livest Sci 109:19–23CrossRefGoogle Scholar
  8. Chen L, Li P, Wang J et al (2009) Catabolism of nutritionally essential amino acids in developing porcine enterocytes. Amino Acids. doi: 10.1007/s00726-009-0268-1
  9. Clowes EJ, Aherne FX, Baracos VE (2005) Skeletal muscle protein mobilization during the progression of lactation. Am J Physiol Endocrinol Metab 288:E564–E572PubMedCrossRefGoogle Scholar
  10. Coeffier M, Claeyssens S, Hecketsweiler B et al (2003) Enteral glutamine stimulates protein synthesis and decreases ubiquitin mRNA level in human gut mucosa. Am J Physiol 285:G266–G273Google Scholar
  11. Corl BA, Odle J, Niu X et al (2008) Arginine activates intestinal p70(S6k) and protein synthesis in piglet rotavirus enteritis. J Nutr 138:24–29PubMedGoogle Scholar
  12. Cox JD (1970) Thermochemistry of organic and organometallic compounds. Academic Press, New York, pp 1–643Google Scholar
  13. Curis E, Crenn P, Cynober L (2007) Citrulline and the gut. Curr Opin Clin Nutr Metab Care 10:620–626PubMedCrossRefGoogle Scholar
  14. Curthoys NP, Watford M (1995) Regulation of glutaminase activity and glutamine metabolism. Annu Rev Nutr 15:133–159PubMedCrossRefGoogle Scholar
  15. Davis TA, Fiorotto ML (2009) Regulation of muscle growth in neonates. Curr Opin Clin Nutr Metab Care 12:78–85PubMedCrossRefGoogle Scholar
  16. Davis PK, Wu G (1998) Compartmentation and kinetics of urea cycle enzymes in porcine enterocytes. Comp Biochem Physiol B 119:527–537PubMedCrossRefGoogle Scholar
  17. Dekaney CM, Wu G, Yin YL, Jaeger LA (2008) Regulation of ornithine aminotransferase gene expression and activity by all-trans retinoic acid in Caco-2 intestinal epithelial cells. J Nutr Biochem 19:674–681PubMedCrossRefGoogle Scholar
  18. Deng ZY, Zhang JW, Wu GY et al (2007) Dietary supplementation with polysaccharides from Semen cassiae enhances immunoglobulin production and interleukin gene expression in early-weaned piglets. J Sci Food Agric 87:1868–1873CrossRefGoogle Scholar
  19. Deng D, Yin YL, Chu WY et al (2008) Impaired translation-initiation activation and reduced protein synthesis in weaned piglets fed a low-protein diet. J Nutr Biochem. doi: 10.1016/j.jnutbio.2008.05.014
  20. Edmonds MS, Baker DH (1987) Amino acid excesses for young pigs: effects of excess methionine, tryptophan, threonine or leucine. J Anim Sci 64:1664–1671PubMedGoogle Scholar
  21. El Idrissi A (2008) Taurine increases mitochondrial buffering of calcium: role in neuroprotection. Amino Acids 34:321–328PubMedCrossRefGoogle Scholar
  22. Elango R, Ball RO, Pencharz PB (2009) Amino acid requirements in humans: with a special emphasis on the metabolic availability of amino acids. Amino Acids. doi: 10.1007/s00726-009-0234-y
  23. El-Kadi SW, Balwin RL, Sunny NE et al (2006) Intestinal protein supply alters amino acid, but not glucose, metabolism by the sheep gastrointestinal tract. J Nutr 136:1261–1269PubMedGoogle Scholar
  24. Escobar J, Frank JW, Suryawan A et al (2005) Physiological rise in plasma leucine stimulates muscle protein synthesis in neonatal pigs by enhancing translation initiation factor activation. Am J Physiol Endocrinol Metab 288:E914–E921PubMedCrossRefGoogle Scholar
  25. Escobar J, Frank JW, Suryawan A et al (2006) Regulation of cardiac and skeletal muscle protein synthesis by individual branched-chain amino acids in neonatal pigs. Am J Physiol Endocrinol Metab 290:E612–E621PubMedCrossRefGoogle Scholar
  26. Fang ZF, Luo J, Qi ZL et al (2009) Effects of 2-hydroxy-4-methylthiobutyrate on portal plasma flow and net portal appearance of amino acids in piglets. Amino Acids 36:501–509PubMedCrossRefGoogle Scholar
  27. Field CJ, Johnson IR, Schley PD (2002) Nutrients and their role in host resistance to infection. J Leukoc Biol 71:16–32PubMedGoogle Scholar
  28. Firkins JL, Hristov AN, Hall MB et al (2006) Integration of ruminal metabolism in dairy cattle. J Dairy Sci 89(Suppl 1):E31–E51PubMedCrossRefGoogle Scholar
  29. Flynn NE, Knabe DA, Mallick BK, Wu G (2000) Postnatal changes of plasma amino acids in suckling pigs. J Anim Sci 78:2369–2375PubMedGoogle Scholar
  30. Flynn NE, Bird JG, Guthrie AS (2008) Glucocorticoid regulation of amino acid and polyamine metabolism in the small intestine. Amino Acids. doi: 10.1007/s00726-008-0206-7
  31. Frank JW, Escobar J, Hguyen HV et al (2007) Oral N-carbamylglutamate supplementation increases protein synthesis in skeletal muscle of piglets. J Nutr 137:315–319PubMedGoogle Scholar
  32. Fu WJ, Haynes TE, Kohli R et al (2005) Dietary l-arginine supplementation reduces fat mass in Zucker diabetic fatty rats. J Nutr 135:714–721PubMedGoogle Scholar
  33. Fuller MF, Redes PJ (1998) Nitrogen cycling in the gut. Annu Rev Nutr 18:385–411PubMedCrossRefGoogle Scholar
  34. Galli F (2007) Amino acid and protein modification by oxygen and nitrogen species. Amino Acids 32:497–499CrossRefGoogle Scholar
  35. Gao HJ, Wu G, Spencer TE et al (2009a) Select nutrients in the ovine uterine lumen: I. Amino acids, glucose and ions in uterine lumenal flushings of cyclic and pregnant ewes. Biol Reprod 80:86–93PubMedCrossRefGoogle Scholar
  36. Gao HJ, Wu G, Spencer TE et al (2009b) Select nutrients in the ovine uterine lumen: II. Glucose transporters in the uterus and peri-implantation conceptuses. Biol Reprod 80:94–104PubMedCrossRefGoogle Scholar
  37. Gao HJ, Wu G, Spencer TE et al (2009c) Select nutrients in the ovine uterine lumen: III. Expression of cationic amino acid transporters in ovine uterus and peri-implantation conceptuses. Biol Reprod 80:602–609PubMedCrossRefGoogle Scholar
  38. Gao HJ, Wu G, Spencer TE et al (2009d) Select nutrients in the ovine uterine lumen: IV. Expression of neutral and acidic amino acid transporters in ovine uteri and peri-implantation conceptuses. Biol Reprod. doi: 10.1095/biolreprod.108.075440 Google Scholar
  39. Gao HJ, Wu G, Spencer TE et al (2009e) Select nutrients in the ovine uterine lumen: V. Nitric oxide synthase, GTP cyclohydrolase and ornithine decarboxylase in ovine uteri and peri-implantation conceptuses. Biol Reprod. doi: 10.1095/biolreprod.108.075473 Google Scholar
  40. Grillo MA, Colombatto S (2007) S-Adenosylmethionine and radical-based catalysis. Amino Acids 32:197–202PubMedCrossRefGoogle Scholar
  41. Grimble RF (2006) The effects of sulfur amino acids intake on immune function in humans. J Nutr 136:1660S–1665SPubMedGoogle Scholar
  42. Ha EM, Choi CT, Bae YS, Lee WJ (2005) A direct role for dual oxidase in Drosophila gut immunity. Science 310:847–850PubMedCrossRefGoogle Scholar
  43. Haynes TE, Li P, Li X et al (2009) l-Glutamine or l-alanyl-l-glutamine prevents oxidant- or endotoxin-induced death of neonatal enterocytes. Amino Acids. doi: 10.1007/s00726-009-0243-x
  44. He QH, Kong XF, Wu G et al (2008) Metabolomic analysis of the response of growing pigs to dietary l-arginine supplementation. Amino Acids. doi: 10.1007/s00726-008-0192-9
  45. Hill JO, Peters JC, Catenacci VA, Wyatt HR (2008) International strategies to address obesity. Obes Rev 9(Suppl 1):41–47PubMedCrossRefGoogle Scholar
  46. Hu CA, Williams DB, Zhaorigetu S et al (2008a) Functional genomics and SNP analysis of human genes encoding proline metabolic enzymes. Amino Acids 35:655–664PubMedCrossRefGoogle Scholar
  47. Hu CA, Khalil S, Zhaorigetu S et al (2008b) Human Δ1-pyrroline-5-carboxylate synthase: function and regulation. Amino Acids 35:665–672PubMedCrossRefGoogle Scholar
  48. Huang YF, Wang YX, Watford M (2007) Glutamine directly downregulates glutamine synthetase protein levels in mouse C2C12 skeletal muscle myotubes. J Nutr 137:1357–1362PubMedGoogle Scholar
  49. Jobgen WS, Fried SK, Fu WJ et al (2006) Regulatory role for the arginine-nitric oxide pathway in metabolism of energy substrates. J Nutr Biochem 17:571–588PubMedCrossRefGoogle Scholar
  50. Jobgen W, Meininger CJ, Jobgen SC et al (2009a) Dietary l-arginine supplementation reduces white-fat gain and enhances skeletal muscle and brown fat masses in diet-induced obese rats. J Nutr 139:230–237PubMedGoogle Scholar
  51. Jobgen W, Fu WJ, Gao H et al (2009b) High fat feeding and dietary l-arginine supplementation differentially regulate gene expression in rat white adipose tissue. Amino Acids. doi: 10.1007/s00726-009-0246-7
  52. John JPP, Oh JE, Pollak A, Lubec G (2008) Identification and characterization of arsenite (+3 oxidation state) methyltransferase (AS3MT) in mouse neuroblastoma cell line N1E-115. Amino Acids 35:355–358PubMedCrossRefGoogle Scholar
  53. Katane M, Hanai T, Furuchi T et al (2008) Hyperactive mutants of mouse d-aspartate oxidase: mutagenesis of the active site residue serine. Amino Acids 35:75–82PubMedCrossRefGoogle Scholar
  54. Kilberg MS, Pan YX, Chen H, Leung-Pineda V (2005) Nutritional control of gene expression: how mammalian cells respond to amino acid limitation. Annu Rev Nutr 25:59–85PubMedCrossRefGoogle Scholar
  55. Kim SW, Wu G (2004) Dietary arginine supplementation enhances the growth of milk-fed young pigs. J Nutr 134:625–630PubMedGoogle Scholar
  56. Kim SW, Wu G (2008) Regulatory role for amino acids in mammary gland growth and milk synthesis. Amino Acids. doi: 10.1007/s00726-008-0151-5
  57. Kohli R, Meininger CJ, Haynes TE et al (2004) Dietary l-arginine supplementation enhances endothelial nitric oxide synthesis in streptozotocin-induced diabetic rats. J Nutr 134:600–608PubMedGoogle Scholar
  58. Kong XF, Yin YL, He QH et al (2008) Dietary supplementation with Chinese herbal powder enhances ileal digestibilities and serum concentrations of amino acids in young pigs. Amino Acids. doi: 10.1007/s00726-008-0176-9
  59. Kwon H, Spencer TE, Bazer FW, Wu G (2003a) Developmental changes of amino acids in ovine fetal fluids. Biol Reprod 68:1813–1820PubMedCrossRefGoogle Scholar
  60. Kwon H, Wu G, Bazer FW, Spencer TE (2003b) Developmental changes in polyamine levels and synthesis in the ovine conceptus. Biol Reprod 69:1626–1634PubMedCrossRefGoogle Scholar
  61. Kwon H, Wu G, Meininger CJ et al (2004) Developmental changes in nitric oxide synthesis in the ovine conceptus. Biol Reprod 70:679–686PubMedCrossRefGoogle Scholar
  62. Leong HX, Simkevich C, Lesieur-Brooks A et al (2006) Short-term arginine deprivation results in large-scale modulation of hepatic gene expression in both normal and tumor cells: microarray bioinformatics analysis. Nutr Metab 3:37CrossRefGoogle Scholar
  63. Li P, Yin YL, Li DF, Kim SW, Wu G (2007) Amino acids and immune function. Br J Nutr 98:237–252PubMedCrossRefGoogle Scholar
  64. Li P, Mai KS, Trushenski J, Wu G (2008) New developments in fish amino acid nutrition: towards functional and environmentally oriented aquafeeds. Amino Acids. doi: 10.1007/s00726-008-0171-1
  65. Li X, Bazer FW, Gao H et al (2009) Amino acids and gaseous signaling. Amino Acids. doi: 10.1007/s00726-009-0264-5
  66. Liao XH, Majithia A, Huang XL, Kimmel AR (2008) Growth control via TOR kinase signaling, an intracellular sensor of amino acids and energy availability, with crosstalk potential to proline metabolism. Amino Acids 35:761–770PubMedCrossRefGoogle Scholar
  67. Lucotti P, Setola E, Monti LD et al (2006) Beneficial effect of a long-term oral l-arginine treatment added to a hypocaloric diet and exercise training program in obese, insulin-resistant type 2 diabetic patients. Am J Physiol Endocrinol Metab 291:E906–E912PubMedCrossRefGoogle Scholar
  68. Lupi A, Tenni R, Rossi A et al (2008) Human prolidase and prolidase deficiency. Amino Acids 35:739–752PubMedCrossRefGoogle Scholar
  69. Lynch CJ, Hutson SM, Patson BJ et al (2002) Tissue-specific effects of chronic dietary leucine and norleucine supplementation on protein synthesis in rats. Am J Physiol Endocrinol Metab 283:E824–E835PubMedGoogle Scholar
  70. Macchiarulo A, Camaioni E, Nuti R, Pellicciari RC (2008) Highlights at the gate of tryptophan catabolism: a review on the mechanisms of activation and regulation of indoleamine 2,3-dioxygenase (IDO), a novel target in cancer disease. Amino Acids. doi: 10.1007/s00726-008-0137-3
  71. Maclennan PA, Brown RA, Rennie MJ (1987) A positive relationship between protein synthetic rate and intracellular glutamine concentration in perfused rat skeletal muscle. FEBS Lett 215:187–191PubMedCrossRefGoogle Scholar
  72. Maclennan PA, Smith K, Weryk B et al (1988) Inhibition of protein breakdown by glutamine in perfused rat skeletal muscle. FEBS Lett 237:133–136PubMedCrossRefGoogle Scholar
  73. Manna P, Sinha M, Sil PC (2009) Taurine plays a beneficial role against cadmium-induced oxidative renal dysfunction. Amino Acids 36:417–428PubMedCrossRefGoogle Scholar
  74. Mannick JB (2007) Regulation of apoptosis by protein S-nitrosylation. Amino Acids 32:523–526PubMedCrossRefGoogle Scholar
  75. Manso Filho HC, Costa HE, Wu G et al (2009) Equine placenta expresses glutamine synthetase. Vet Res Commun 33:175–182PubMedCrossRefGoogle Scholar
  76. Marliss EB, Chevalier S, Gougeon R et al (2006) Elevations of plasma methylarginines in obesity and ageing are related to insulin sensitivity and rates of protein turnover. Diabetologia 49:351–359PubMedCrossRefGoogle Scholar
  77. Martin PM, Sutherland AE, Van Winkle LJ (2003) Amino acid transport regulates blastocyst implantation. Biol Reprod 69:1101–1108PubMedCrossRefGoogle Scholar
  78. Mateo RD, Wu G, Bazer FW et al (2007) Dietary l-arginine supplementation enhances the reproductive performance of gilts. J Nutr 137:652–656PubMedGoogle Scholar
  79. Mateo RD, Wu G, Moon HK et al (2008) Effects of dietary arginine supplementation during gestation and lactation on the performance of lactating primiparous sows and nursing piglets. J Anim Sci 86:827–835PubMedCrossRefGoogle Scholar
  80. Meijer AJ (2003) Amino acids as regulators and components of nonproteinogenic pathways. J Nutr 133:2057S–2062SPubMedGoogle Scholar
  81. Meijer AJ, Dubbelhuis PF (2004) Amino acid signaling and the integration of metabolism. Biochem Biophys Res Commun 313:397–403PubMedCrossRefGoogle Scholar
  82. Melchior D, Le Floc’h N, Seve B (2003) Effect of chronic lung inflammation on tryptophan metabolism in piglets. Adv Exp Med Biol 527:359–362PubMedGoogle Scholar
  83. Montanez R, Rodriguez-Caso C, Sanchez-Jimenez F, Medina MA (2008) In silico analysis of arginine catabolism as a source of nitric oxide or polyamines in endothelial cells. Amino Acids 34:223–229PubMedCrossRefGoogle Scholar
  84. Morris SM Jr (2007) Arginine metabolism: boundaries of our knowledge. J Nutr 137:1602S–1609SPubMedGoogle Scholar
  85. Nakashima K, Yakabe Y, Ishida A et al (2007) Suppression of myofibrillar proteolysis in chick skeletal muscles by α-ketoisocaproate. Amino Acids 33:499–503PubMedCrossRefGoogle Scholar
  86. Newsholme P, Brennnan L, Rubi B, Maechler P (2005) New insights into amino acid metabolism, beta-cell function and diabetes. Clin Sci 108:185–194PubMedCrossRefGoogle Scholar
  87. Novelli A, Tasker RAR (2008) Excitatory amino acids in epilepsy: from the clinics to the laboratory. Amino Acids 32:295–297CrossRefGoogle Scholar
  88. Orlando GF, Wolf G, Engelmann M (2008) Role of neuronal nitric oxide synthase in the regulation of the neuroendocrine stress response in rodents: insights from mutant mice. Amino Acids 35:17–27PubMedCrossRefGoogle Scholar
  89. Ou DY, Li DF, Cao YH et al (2007) Dietary supplementation with zinc oxide decreases expression of the stem cell factor in the small intestine of weanling pigs. J Nutr Biochem 18:820–826PubMedCrossRefGoogle Scholar
  90. Palii SS, Kays CE, Deval C et al (2008) Specificity of amino acid regulated gene expression: analysis of gene subjected to either complete or single amino acid deprivation. Amino Acids. doi: 10.1007/s00726-008-0199-2
  91. Perta-Kajan J, Twardowski T, Jakubowski H (2007) Mechanisms of homocysteine toxicity in humans. Amino Acids 32:561–572CrossRefGoogle Scholar
  92. Phang JM, Donald SP, Pandhare J, Liu Y (2008) The metabolism of proline, as a stress substrate, modulates carcinogenic pathways. Amino Acids 35:681–690PubMedCrossRefGoogle Scholar
  93. Platten M, Ho PP, Youssef S et al (2005) Treatment of autoimmune neuroinflammation with a synthetic tryptophan metabolite. Science 310:850–855PubMedCrossRefGoogle Scholar
  94. Ptolemy AS, Lee R, Britz-McKibbin P (2007) Strategies for comprehensive analysis of amino acid biomarkers of oxidative stress. Amino Acids 33:3–18PubMedCrossRefGoogle Scholar
  95. Rees WD, Wilson FA, Maloney CA (2006) Sulfur amino acid metabolism in pregnancy: the impact of methionine in the maternal diet. J Nutr 136:1701S–1705SPubMedGoogle Scholar
  96. Rhoads JM, Wu G (2008) Glutamine, arginine, and leucine signaling in the intestine. Amino Acids. doi: 10.1007/s00726-008-0225-4
  97. Rhoads JM, Argenzio RA, Chen WN et al (1997) l-Glutamine stimulates intestinal cell proliferation and activates mitogen-activated protein kinases. Am J Physiol Gastrointest Liver Physiol 272:G943–G953Google Scholar
  98. Rhoads JM, Niu X, Odle J, Graves LM (2006) Role of mTOR signaling in intestinal cell migration. Am J Physiol Gastrointest Liver Physiol 291:G510–G517PubMedCrossRefGoogle Scholar
  99. Rhoads JM, Niu XM, Surendran S et al (2008) Arginine stimulates intestinal epithelial cell migration via a mechanism requiring both nitric oxide and p70s6k signaling. J Nutr 138:1652–1657PubMedGoogle Scholar
  100. Rider JE, Hacker A, Mackintosh CA et al (2007) Spermine and spermidine mediate protection against oxidative damage caused by hydrogen peroxide. Amino Acids 33:231–240PubMedCrossRefGoogle Scholar
  101. Riedijk MA, Stoll B, Chacko S et al (2007) Methionine transmethylation and transsulfuration in the piglet gastrointestinal tract. Proc Natl Acad Sci USA 104:3408–3413PubMedCrossRefGoogle Scholar
  102. Sahai A, Pan XM, Paul R et al (2006) Roles of phosphatidylinositol 3-kinase and osteopontin in steatosis and aminotransferase release by hepatocytes treated with methionine-choline-deficient medium. Am J Physiol Gastrointest Liver Physiol 291:G55–G62PubMedCrossRefGoogle Scholar
  103. Sancak Y, Peterson TR, Shaul YD et al (2008) The Rag GTPases bind raptor and mediate amino acid signaling to mTORC1. Science 320:1496–1501PubMedCrossRefGoogle Scholar
  104. Sarbassov D, Guertin D, Ali S, Sabatini D (2005) Phosphorylation and regulation of Akt/PKB by the rictor-mTOR complex. Science 307:1098–1101PubMedCrossRefGoogle Scholar
  105. Scolari MJ, Acosta GB (2007) d-Serine: a new world in the glutaamatergic neuro-glial language. Amino Acids 33:563–574PubMedCrossRefGoogle Scholar
  106. Self JT, Spencer TE, Johnson GA et al (2004) Glutamine synthesis in the developing porcine placenta. Biol Reprod 70:1444–1451PubMedCrossRefGoogle Scholar
  107. She P, Reid TM, Bronson SK et al (2007) Disruption of BCATm in mice leads to increased energy expenditure associated with the activation of a futile protein turnover cycle. Cell Metab 6:181–194PubMedCrossRefGoogle Scholar
  108. Shi W, Meininger CJ, Haynes TE et al (2004) Regulation of tetrahydrobiopterin synthesis and bioavailability in endothelial cells. Cell Biochem Biophys 41:415–433PubMedCrossRefGoogle Scholar
  109. Smith SB, Kawachi H, Choi CB et al (2008) Cellular regulation of bovine intramuscular adipose tissue development and composition. J Anim Sci. doi: 10.2527/jas.2008-1340 Google Scholar
  110. Stipanuk MH, Ueki I, Dominy JE et al (2008) Cysteine dioxygenase: a robust system for regulation of cellular cysteine levels. Amino Acids. doi: 10.1007/s00726-008-0202-y
  111. Stoll B, Henry J, Reeds PJ et al (1998) Catabolism dominates the first-pass intestinal metabolism of dietary essential amino acids in milk protein-fed piglets. J Nutr 128:606–614PubMedGoogle Scholar
  112. Suenaga R, Tomonaga S, Yamane H et al (2008) Intracerebroventricular injection of l-arginine induces sedative and hypnotic effects under an acute stress in neonatal chicks. Amino Acids 35:139–146PubMedCrossRefGoogle Scholar
  113. Sugita Y, Takao K, Toyama Y, Shirahata A (2007) Enhancement of intestinal absorption of macromolecules by spermine in rats. Amino Acids 33:253–260PubMedCrossRefGoogle Scholar
  114. Sun YP, Nonobe E, Kobayashi Y et al (2002) Characterization and expression of l-amino acid oxidase of mouse milk. J Biol Chem 277:19080–19086PubMedCrossRefGoogle Scholar
  115. Suryawan A, O’Connor PMJ, Bush JA et al (2008a) Differential regulation of protein synthesis by amino acids and insulin in peripheral and visceral tissues of neonatal pigs. Amino Acids. doi: 10.1007/s00726-008-0149-z
  116. Suryawan A, Jeyapalan AS, Orellana RA et al (2008b) Leucine stimulates protein synthesis in skeletal muscle of neonatal pigs by enhancing mTOR1 activation. Am J Physiol Endocrinol Metab 295:E868–E875PubMedCrossRefGoogle Scholar
  117. Tan BE, Li XG, Kong XF et al (2008a) Dietary l-arginine supplementation enhances the immune status in early-weaned piglets. Amino Acids. doi: 10.1007/s00726-008-0155-1
  118. Tan BE, Yin YL, Liu ZQ et al (2008b) Dietary l-arginine supplementation increases muscle gain and reduces body fat mass in growing-finishing pigs. Amino Acids. doi: 10.1007/s00726-008-0148-0
  119. Tischler ME, Desautels M, Goldberg AL (1982) Does leucine, leucyl-transfer RNA, or some metabolite of leucine regulate protein synthesis and degradation in skeletal and cardiac muscle? J Biol Chem 257:1613–1621PubMedGoogle Scholar
  120. Tujioka K, Okuyama S, Yokogoshi H et al (2007) Dietary γ-aminobutyric acid affects the brain protein synthesis rate in young rats. Amino Acids 32:255–260PubMedCrossRefGoogle Scholar
  121. Van Brummelen R, du Toit D (2007) l-Methionine as immune supportive supplement: a clinical evaluation. Amino Acids 33:157–163PubMedCrossRefGoogle Scholar
  122. Van Goudoever JB, Stoll B, Henry JF et al (2000) Adaptive regulation of intestinal lysine metabolism. Proc Natl Acad Sci USA 97:11620–11625PubMedCrossRefGoogle Scholar
  123. Wang X, Qiao SY, Yin YL et al (2007) A deficiency or excess of dietary threonine reduces protein synthesis in jejunum and skeletal muscle of young pigs. J Nutr 137:1442–1446PubMedGoogle Scholar
  124. Wang JJ, Chen LX, Li P et al (2008a) Gene expression is altered in piglet small intestine by weaning and dietary glutamine supplementation. J Nutr 138:1025–1032PubMedGoogle Scholar
  125. Wang WW, Qiao SY, Li DF (2008b) Amino acids and gut function. Amino Acids. doi: 10.1007/s00726-008-0152-4
  126. Wang JJ, Wu G, Zhou HJ, Wang FL (2008c) Emerging technologies for amino acid nutrition research in the post-genome era. Amino Acids. doi: 10.1007/s00726-008-0193-8
  127. Wang X, Ou D, Yin J et al (2009) Proteomic analysis reveals altered expression of proteins related to glutathione metabolism and apoptosis in the small intestine of zinc oxide-supplemented piglets. Amino Acids. doi: 10.1007/s00726-009-0242-y
  128. Watford M, Wu G (2005) Glutamine metabolism in uricotelic species: variation in skeletal muscle glutamine synthetase, glutaminase, glutamine levels and rates of protein synthesis. Comp Biochem Physiol B 140:607–614PubMedCrossRefGoogle Scholar
  129. Willis A, Beander HU, Steel G, Valle D (2008) PRODH variants and risk for schizophrenia. Amino Acids 35:673–679PubMedCrossRefGoogle Scholar
  130. Wu G (1995) Urea synthesis in enterocytes of developing pigs. Biochem J 312:717–723PubMedGoogle Scholar
  131. Wu G (1997) Synthesis of citrulline and arginine from proline in enterocytes of postnatal pigs. Am J Physiol 272:G1382–G1390PubMedGoogle Scholar
  132. Wu G (1998) Intestinal mucosal amino acid catabolism. J Nutr 128:1249–1252PubMedGoogle Scholar
  133. Wu G, Knabe DA (1994) Free and protein-bound amino acids in sow’s colostrums and milk. J Nutr 124:415–424PubMedGoogle Scholar
  134. Wu G, Meininger CJ (2002) Regulation of nitric oxide synthesis by dietary factors. Annu Rev Nutr 22:61–86PubMedCrossRefGoogle Scholar
  135. Wu G, Meininger CJ (2009) Nitric oxide and vascular insulin resistance. Biofactors 35:21–27CrossRefPubMedGoogle Scholar
  136. Wu G, Morris SM Jr (1998) Arginine metabolism: nitric oxide and beyond. Biochem J 336:1–17PubMedGoogle Scholar
  137. Wu G, Thompson JR (1987) Ketone bodies inhibit leucine degradation in chick skeletal muscle. Int J Biochem 19:937–943PubMedCrossRefGoogle Scholar
  138. Wu G, Thompson JR (1990) The effect of glutamine on protein turnover in chick skeletal muscle in vitro. Biochem J 265:593–598PubMedGoogle Scholar
  139. Wu G, Bazer FW, Tuo W (1995) Developmental changes of free amino acid concentrations in fetal fluids of pigs. J Nutr 125:2859–2868PubMedGoogle Scholar
  140. Wu G, Meier SA, Knabe DA (1996a) Dietary glutamine supplementation prevents jejunal atrophy in weaned pigs. J Nutr 126:2578–2584PubMedGoogle Scholar
  141. Wu G, Bazer FW, Tuo W et al (1996b) Unusual abundance of arginine and ornithine in porcine allantoic fluid. Biol Reprod 54:1261–1265PubMedCrossRefGoogle Scholar
  142. Wu G, Knabe DA, Flynn NE et al (1996c) Arginine degradation in developing porcine enterocytes. Am J Physiol Gastrointest Liver Physiol 271:G913–G919Google Scholar
  143. Wu G, Bazer FW, Cudd TA et al (2004a) Maternal nutrition and fetal development. J Nutr 134:2169–2172PubMedGoogle Scholar
  144. Wu G, Fang YZ, Yang S et al (2004b) Glutathione metabolism and its implications for health. J Nutr 134:489–492PubMedGoogle Scholar
  145. Wu G, Knabe DA, Kim SW (2004c) Arginine nutrition in neonatal pigs. J Nutr 134:2783S–2790SPubMedGoogle Scholar
  146. Wu G, Bazer FW, Hu J et al (2005) Polyamine synthesis from proline in the developing porcine placenta. Biol Reprod 72:842–850PubMedCrossRefGoogle Scholar
  147. Wu G, Bazer FW, Wallace JM, Spencer TE (2006) Intrauterine growth retardation: implications for the animal sciences. J Anim Sci 84:2316–2337PubMedCrossRefGoogle Scholar
  148. Wu G, Bazer FW, Davis TA et al (2007a) Important roles for the arginine family of amino acids in swine nutrition and production. Livest Sci 112:8–22CrossRefGoogle Scholar
  149. Wu G, Bazer FW, Cudd TA et al (2007b) Pharmacokinetics and safety of arginine supplementation in animals. J Nutr 137:1673S–1680SPubMedGoogle Scholar
  150. Wu G, Collins JK, Perkins-Veazie P et al (2007c) Dietary supplementation with watermelon pomace juice enhances arginine availability and ameliorates the metabolic syndrome in Zucker diabetic fatty rats. J Nutr 137:2680–2685PubMedGoogle Scholar
  151. Wu G, Bazer FW, Datta S et al (2008a) Proline metabolism in the conceptus: implications for fetal growth and development. Amino Acids 35:691–702PubMedCrossRefGoogle Scholar
  152. Wu G, Bazer FW, Davis TA et al (2008b) Arginine metabolism and nutrition in growth, health and disease. Amino Acids. doi: 10.1007/s00726-008-0210-y
  153. Xia Y, Wen HY, Young ME et al (2003) Mammalian target of rapamycin and protein kinase A signaling mediate the cardiac transcriptional response to glutamine. J Biol Chem 278:13143–13150PubMedCrossRefGoogle Scholar
  154. Yan GR, He QY (2008) Functional proteomics to identify critical proteins in signal transduction pathways. Amino Acids 35:267–274PubMedCrossRefGoogle Scholar
  155. Yao K, Yin YL, Chu WY et al (2008) Dietary arginine supplementation increases mTOR signaling activity in skeletal muscle of neonatal pigs. J Nutr 138:867–872PubMedGoogle Scholar
  156. Zeng XF, Wang FL, Fan X et al (2008) Dietary arginine supplementation during early pregnancy enhances embryonic survival in rats. J Nutr 138:1421–1425PubMedGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Animal Science, Faculty of NutritionTexas A&M UniversityCollege StationUSA

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