Tak! Piszę też o tym w mojej książce, bodaj w rozdziale: "Arginina - hormonem".

To dosyć ciekawe zagadnienie, ale wymagałoby szerokiego wyjaśnienia...

Axel, cenna inicjatywa!

Okej, to o czym pisałem.

***

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: pam.vleeuwen@vumc.nl.


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

Zgadza się! Jak mówię - piszę tęż o tym w "Legalnych anabolikach".

Tak ale tutaj mamy teraz popracie badaniem

Jasne! Podobne wyniki uzyskiwano już wcześniej, ale na tym właśnie polega nauka: na weryfikacji wcześniejszych badań - kolejnymi.

L-glutamina nie wplywa na wewnatrzkomórkowy poziom l-argininy:

Interactions between L-arginine and L-glutamine change endothelial NO production. An effect independent of NO synthase substrate availability.
J F Arnal, T Münzel, R C Venema, N L James, C L Bai, W E Mitch, and D G Harrison
Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Small right arrow pointing to: This article has been cited by other articles in PMC.
Abstract
The effect of extracellular L-arginine and L-glutamine on nitric oxide (NO) release was studied in cultured bovine aortic endothelial cells and in rabbit aortic rings. Increasing L-arginine (0.01 to 10 mM) did not alter NO release from cultured endothelial cells or modify endothelium-dependent relaxation to acetylcholine in isolated vessels. L-Glutamine (0.6 and 2 mM) inhibited NO release from cultured cells (in response to bradykinin) and from aortic rings (in response to acetylcholine or ADP). L-Arginine (0.1-10 mM) dose-dependently reversed the L-glutamine inhibition of receptor-stimulated NO release in both models. In contrast to its inhibitory response to receptor-mediated stimuli, glutamine alone slightly potentiated NO release in both models when the calcium ionophore, A23187, was added. Furthermore, cultured cells incubated with L-arginine (0.01-10 mM), in the presence or absence of glutamine, released similar amounts of NO in response to A23187. L-Glutamine did not affect intracellular L-arginine levels. Neither D-glutamine nor D-arginine affected NO release or endothelium-dependent vascular relaxation. L-Glutamine had no effect on the activity of endothelial NOS assessed by L-arginine to L-citrulline conversion. These findings show that in the absence of L-glutamine, manipulating intracellular L-arginine levels over a wide range does not affect NO release. L-Glutamine in concentrations circulating in vivo may tonically inhibit receptor-mediated NO release by interfering with signal transduction. One mechanism by which L-arginine may enhance NO release is via reversal of the inhibitory effect of L-glutamine, but apparently independently of enhancing NO synthase substrate.

Niestety badanie nie jest robione na ludzkich komórkach...

generalnie: wolałbym suplementowac argininę - by zwiekszyc poziom argininy, niz glutaminę w tym samym celu.

Zmieniony przez - faftaq w dniu 2010-03-13 16:21:14

Nie zwiększa w śródbłonku naczyń, ale zwiększa w komórkach mięśniowych. Jest raczej bez znaczenia w oddziaływaniu na tlenek azotu, za to pożyteczna w aktywacji czynnika transkrypcyjnego - SRF, kontrolującego syntezę większości białek mięśniowych - aktyny, miozyny, troponiny, tropomiozyny i dystrofiny.
To dosyć skomplikowane i trudne do wyjaśnienia w dwóch słowach... Wyjaśniam to w książce!

wniosek nasuwa sie taki ze skoro jedynie 20% glutaminy dociera do komorek miesniowych to wyjsciem bylaby glutamina w zastrzykach. prawda? co myslicie