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http://www.ajcn.org/cgi/content/abstract/90/1/95
Enteral administration of alanyl-[2-15N]glutamine contributes more to the de novo synthesis of arginine than does intravenous infusion of the dipeptide in humans 1,2,3,4,5
Gerdien C Ligthart-Melis, Marcel CG van de Poll, Mechteld AR Vermeulen, Petra G Boelens, M Petrousjka van den Tol, Cors van Schaik, Jean-Pascal De Bandt, Nicolaas EP Deutz, Cornelis HC Dejong and Paul AM van Leeuwen
1 From the Department of Surgery, VU University Medical Center, Amsterdam, Netherlands (GCL-M, MARV, PGB, MPvdT, CvS, and PAMvL); the Department. of Surgery, University Hospital Maastricht & Nutrition and Toxicology Research Institute Maastricht, Maastricht, Netherlands (MCGvdP, NEPD, and CHCD); and Clinical Biochemistry, Université Paris Descartes, Paris, France (J-PDB).
2 GCL-M and MCGvdP contributed equally to this work and share first authorship.
3 Supported by a grant from the Netherlands Organization for Health Research and Development to PGB (920-03-185 AGIKO) and by a grant from Fresenius-Kabi, Bad Homburg, Germany.
4 Present address for NEPD: Center for Translational Research on Aging & Longevity, Donald W Reynolds Institute of Aging, University of Arkansas for Medical Sciences, Little Rock, AR.
5 Address correspondence to PAM van Leeuwen, Department of Surgery, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, Netherlands. E-mail:
[email protected].
Background: We previously confirmed in humans the existence of a pathway of glutamine into citrulline and arginine, which is preferentially stimulated by luminally provided glutamine. However, because glutamine is unstable, we tested this pathway with a stable dipeptide of glutamine.
Objectives: The objectives were to explore whether alanyl-glutamine contributes to the synthesis of arginine in humans and whether this depends on the route of administration.
Design: The study was conducted under postabsorptive conditions during surgery. Sixteen patients received alanyl-[2-15N]glutamine enterally or intravenously together with intravenously administered stable-isotope tracers of citrulline and arginine. Blood was collected from an artery, the portal vein, a hepatic vein, and the right renal vein. Arterial and venous enrichments and (tracer) net balances of alanyl-glutamine and glutamine, citrulline, and arginine across the portal-drained viscera, liver, and kidneys were determined. Parametric tests were used to test results (mean ± SEM). P < 0.05 was considered significant.
Results: Twice as much exogenous glutamine was used for the synthesis of citrulline when alanyl-glutamine was provided enterally (5.9 ± 0.6%) than when provided intravenously (2.8 ± 0.3%) (P < 0.01). Consequently, twice as much exogenous glutamine was used for the synthesis of arginine when alanyl-glutamine was provided enterally (5 ± 0.7%) than when provided intravenously (2.4 ± 0.2%) (P < 0.01). However, results at the organ level did not explain the differences due to route of administration.
Conclusions: Alanyl-glutamine contributes to the de novo synthesis of arginine, especially when provided enterally. A stable-isotope study using a therapeutic dose of alanyl-glutamine is needed to investigate the clinical implications of this finding.
Ogólne streszczenie:
Badanie przeprowadzone w Holandii na Uniwersytecie Maastricht dowiodło, że suplementy zawierające alanilo-glutaminę stymulują produkcje argininy w organiźmie. Glutamina bierze udział - według naukowców - w syntezie 64% argininy. Dożylne stosowanie alanilo-glutaminy podwaja poziom argininy, a stosowane doustnie tego suplementu również wywiera klinicznie istotny efekt
Zmieniony przez - MolderDist w dniu 2010-03-10 23:59:59
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