title: Features, causes and consequences of splanchnic sequestration of amino acid in old rats.
abstract: BACKGROUND
  In elderly subjects, splanchnic extraction of amino acids (AA) increases during meals in a process known as splanchnic sequestration of amino acids (SSAA). This process potentially contributes to the age-related progressive decline in muscle mass via reduced peripheral availability of dietary AA. SSAA mechanisms are unknown but may involve an increased net utilization of ingested AA in the splanchnic area.
  
  
  OBJECTIVE
  Using stable isotope methodology in fed adult and old rats to provide insight into age-related SSAA using three hypotheses: 1) an increase in protein synthesis in the gut and/or the liver, 2) an increase in AA oxidation related to an increased ureagenesis, and 3) Kupffer cell (KC) activation consequently to age-related low-grade inflammation.
  
  
  RESULTS
  Splanchnic extraction of Leu (SPELeu) was doubled in old rats compared to adult rats and was not changed after KC inactivation. No age-related effects on gut and liver protein synthesis were observed, but urea synthesis was lower in old rats and negatively correlated to liver Arg utilization. Net whole-body protein synthesis and arterial AA levels were lower in old rats and correlated negatively with SPELeu.
  
  
  CONCLUSIONS
  SSAA is not the consequence of age-related alterations in ureagenesis, gut or liver protein synthesis or of KC activity. However, SSAA may be related to reduced net whole-body protein synthesis and consequently to the reduced lean body mass that occurs during aging.
authors.affiliation: Laboratory of Biological Nutrition EA 4466, Paris Descartes University, Paris, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Jourdan
authors.forename: Nicolaas E P
authors.initials: NE
authors.lastname: Deutz
authors.forename: Luc
authors.initials: L
authors.lastname: Cynober
authors.forename: Christian
authors.initials: C
authors.lastname: Aussel
mesh_terms: D000367:Age Factors; D000375:Aging / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001120:Arginine; D007413:Intestinal Mucosa / Q000378:metabolism; D007728:Kupffer Cells / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008239:Lysine; D014176:Protein Biosynthesis; D051381:Rats; D014781:Viscera / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D001120:Arginine; D008239:Lysine
references.citation: J Nutr. 2000 Dec;130(12):3003-13
references.pmid: 11110860
references.citation: JPEN J Parenter Enteral Nutr. 1999 Jan-Feb;23(1):32-7
references.pmid: 9888415
references.citation: Toxicology. 2007 Nov 30;241(3):106-18
references.pmid: 17900782
references.citation: Biochem J. 1984 Jan 15;217(2):507-16
references.pmid: 6199020
references.citation: Biochem J. 1987 Jul 1;245(1):223-8
references.pmid: 3663148
references.citation: J Leukoc Biol. 1992 Sep;52(3):296-302
references.pmid: 1522388
references.citation: Am J Clin Nutr. 1997 Oct;66(4):880-9
references.pmid: 9322564
references.citation: Lab Anim. 1996 Oct;30(4):347-58
references.pmid: 8938622
references.citation: J Biol Chem. 1988 Mar 5;263(7):3245-9
references.pmid: 3125177
references.citation: Am J Physiol. 1993 May;264(5 Pt 1):E693-8
references.pmid: 8498491
references.citation: Beitr Infusionther Klin Ernahr. 1987;17:167-70
references.pmid: 3689302
references.citation: Age (Dordr). 2009 Jun;31(2):155-62
references.pmid: 19377912
references.citation: Scand J Clin Lab Invest. 1987 Sep;47(5):447-53
references.pmid: 3659823
references.citation: Am J Physiol. 1996 Jun;270(6 Pt 1):G909-18
references.pmid: 8764196
references.citation: J Nutr. 2000 Nov;130(11):2630-5
references.pmid: 11053498
references.citation: Anal Biochem. 1999 Jun 15;271(1):8-17
references.pmid: 10360999
references.citation: Biochim Biophys Acta. 1976 Jul 21;437(2):477-86
references.pmid: 952929
references.citation: Am J Clin Nutr. 2005 Aug;82(2):428-34
references.pmid: 16087989
references.citation: Lab Anim. 2001 Jan;35(1):101-10
references.pmid: 11201286
references.citation: J Gerontol A Biol Sci Med Sci. 2000 Dec;55(12):M716-24
references.pmid: 11129393
references.citation: Clin Nutr. 2001 Aug;20(4):313-7
references.pmid: 11478828
references.citation: Am J Physiol Regul Integr Comp Physiol. 2008 Mar;294(3):R748-55
references.pmid: 18056986
references.citation: Am J Clin Nutr. 2005 Nov;82(5):1065-73
references.pmid: 16280440
references.citation: J Cell Physiol. 1969 Apr;73(2):159-70
references.pmid: 5789918
references.citation: J Lab Clin Med. 2001 Apr;137(4):231-43
references.pmid: 11283518
references.citation: Exp Gerontol. 1992;27(2):191-200
references.pmid: 1381684
references.citation: Am J Physiol. 1992 Sep;263(3 Pt 1):E584-96
references.pmid: 1415540
references.citation: Biochem J. 1993 May 15;292 ( Pt 1):241-7
references.pmid: 8503852
references.citation: Curr Opin Clin Nutr Metab Care. 2008 Jan;11(1):45-9
references.pmid: 18090658
references.citation: J Neurosci Res. 1982;7(4):387-95
references.pmid: 7143488
references.citation: Am J Med. 2006 Jun;119(6):526.e9-17
references.pmid: 16750969
references.citation: Eur J Biochem. 2002 Nov;269(22):5338-49
references.pmid: 12423332
references.citation: J Chromatogr B Analyt Technol Biomed Life Sci. 2007 Sep 1;856(1-2):48-56
references.pmid: 17561452
references.citation: Metabolism. 1970 Sep;19(9):653-63
references.pmid: 5459997
references.citation: Curr Opin Clin Nutr Metab Care. 2009 Jan;12(1):86-90
references.pmid: 19057193
references.citation: Am J Clin Nutr. 1997 Feb;65(2):489-95
references.pmid: 9022534
references.citation: Am J Physiol Endocrinol Metab. 2002 Sep;283(3):E503-13
references.pmid: 12169444
references.citation: J Gerontol A Biol Sci Med Sci. 2002 Dec;57(12):M772-7
references.pmid: 12456735
references.citation: Hum Biol. 1977 Sep;49(3):495-513
references.pmid: 892769
references.citation: Am J Clin Nutr. 2011 May;93(5):997-1005
references.pmid: 21367943
references.citation: J Nutr. 2002 Jan;132(1):95-100
references.pmid: 11773514
references.citation: Am J Physiol Endocrinol Metab. 2000 Aug;279(2):E366-75
references.pmid: 10913037
references.citation: J Nutr. 2001 Sep;131(9 Suppl):2460S-6S; discussion 2486S-7S
references.pmid: 11533294
references.citation: Am J Physiol. 1992 Nov;263(5 Pt 1):E928-34
references.pmid: 1443126
references.citation: J Gerontol A Biol Sci Med Sci. 2007 Sep;62(9):973-8
references.pmid: 17895435
references.citation: Ann Biol Clin (Paris). 1951 Oct-Dec;9(10-11-12):453-66
references.pmid: 14915149
references.citation: JAMA. 2001 Sep 12;286(10):1206-12
references.pmid: 11559266
references.citation: Amino Acids. 2005 Nov;29(3):177-205
references.pmid: 16082501
references.citation: J Nutr Health Aging. 2009 Oct;13(8):717-23
references.pmid: 19657556
references.citation: J Biol Chem. 1981 Mar 25;256(6):2618-20
references.pmid: 7009595
references.citation: Am J Physiol. 1999 Sep;277(3):E513-20
references.pmid: 10484364
references.citation: Mech Ageing Dev. 1987 Jul;39(2):189-99
references.pmid: 2442570
references.citation: J Lab Clin Med. 1951 Jun;37(6):955-8
references.pmid: 14850828