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Originally Posted by tjbentham where are these reports saying that glutamine is useless? i thought it was widely accepted that it aids in recovery and had medical uses, not arguing whether it is or not just if u have some reports. I've had great increase in recovery rates when ive used l glutamine. |
Oxidation of glutamine by the splanchnic bed in humans.
* Haisch M,
* Fukagawa NK,
* Matthews DE.
Departments of Medicine and Chemistry, University of Vermont, Burlington, Vermont 05405, USA.
[1,2-(13)C(2)]glutamine and [ring-(2)H(5)]phenylalanine were infused for 7 h into five postabsorptive healthy subjects on two occasions. On one occasion, the tracers were infused intravenously for 3.5 h and then by a nasogastric tube for 3.5 h. The order of
infusion was reversed on the other occasion. From the plasma tracer enrichment measurements at plateau during the intravenous and nasogastric infusion periods, we determined that 27 +/- 2% of the enterally delivered phenylalanine and 64 +/- 2% of the glutamine were removed on the first pass by the splanchnic bed. Glutamine flux was 303 +/- 8 micromol. kg(-1). h(-1). Of the enterally delivered [(13)C]glutamine tracer, 73 +/- 2% was recovered as exhaled CO(2) compared with 58 +/- 1% of the intravenously infused tracer. The fraction of the enterally delivered tracer that was oxidized specifically on the first pass by the splanchnic bed was 53 +/- 2%, comprising 83% of the total tracer extracted. From the appearance of (13)C in plasma glucose, we estimated that 7 and 10% of the intravenously and nasogastrically infused glutamine tracers, respectively, were converted to glucose. The results for glutamine flux and first-pass extraction were similar to our previously reported values when a [2-(15)N]glutamine tracer [Matthews DE, Morano MA, and Campbell RG, Am J Physiol Endocrinol Metab 264: E848-E854, 1993] was used.
The results of [(13)C]glutamine tracer disposal demonstrate that the major fate of enteral glutamine extraction is for oxidation and that only a minor portion is used for gluconeogenesis.
Free and protein-bound glutamine have identical splanchnic extraction in healthy human volunteers.
* Boza JJ,
* Dangin M,
* Moennoz D,
* Montigon F,
* Vuichoud J,
* Jarret A,
* Pouteau E,
* Gremaud G,
* Oguey-Araymon S,
* Courtois D,
* Woupeyi A,
* Finot PA,
* Ballevre O.
Nestle Research Center, Vers-Chez-Les-Blanc, 1000 Lausanne 26, Switzerland.
The objectives of the present study were to determine the splanchnic extraction of glutamine after ingestion of glutamine-rich protein ((15)N-labeled oat proteins) and to compare it with that of free glutamine and to determine de novo glutamine synthesis before and after glutamine consumption. Eight healthy adults were infused intravenously in the postabsorptive state with L-[1-(13)C]glutamine (3 micromol x kg(-1) x h(-1)) and L-[1-(13)C]lysine (1.5 micromol x kg(-1) x h(-1)) for 8 h. Four hours after the beginning of the infusion, subjects consumed (every 20 min) a liquid formula providing either 2.5 g of protein from (15)N-labeled oat proteins or a mixture of free amino acids that mimicked the oat-amino acid profile and contained L-[2,5-(15)N(2)]glutamine and L-[2-(15)N]lysine. Splanchnic extraction of glutamine reached 62.5 +/- 5.0% and 66.7 +/- 3.9% after administration of (15)N-labeled oat proteins and the mixture of free amino acids, respectively. Lysine splanchnic extraction was also not different (40.9 +/- 11.9% and 34.9 +/- 10.6% for (15)N-labeled oat proteins and free amino acids, respectively). The main conclusion of the present study is that glutamine is equally bioavailable when given enterally as a free amino acid and when protein bound.
Therefore, and taking into consideration the drawbacks of free glutamine supplementation of ready-to-use formulas for enteral nutrition, protein sources naturally rich in this amino acid are the best option for providing stable glutamine.
