Acute depletion of plasma glutamine increases leucine oxidation in prednisone-treated humans.

Autor: Le Bacquer O; INSERM U.539, Centre de Recherche en Nutrition Humaine, Nantes, France., Mauras N, Welch S, Haymond M, Darmaun D
Jazyk: angličtina
Zdroj: Clinical nutrition (Edinburgh, Scotland) [Clin Nutr] 2007 Apr; Vol. 26 (2), pp. 231-8. Date of Electronic Publication: 2006 Nov 13.
DOI: 10.1016/j.clnu.2006.09.010
Abstrakt: Background, Aims & Methods: To determine whether depletion in plasma glutamine worsens the catabolic response to corticosteroids, seven healthy volunteers received oral prednisone for 6 days on two separate occasions, at least 2 weeks apart, and in random order. On the sixth day of each treatment course, they received 5 h intravenous infusions of L-[1-(14)C]-leucine and L-[1-(13)C]-glutamine in the postabsorptive state (1) under baseline conditions (prednisone only day) and (2) after 24h of treatment with phenylbutyrate (prednisone+phenylbutyrate day), a glutamine chelating agent.
Results: Phenylbutyrate treatment was associated with (1) an approximately 15% decline in plasma glutamine concentration (627+/-39 vs. 530+/-31 micromol l(-1); P<0.05), (2) no change in leucine appearance rate, an index of protein breakdown (124+/-9 vs. 128+/-9 micromol kg(-1) h(-1); NS) nor in non-oxidative leucine disposal, an index of whole body protein synthesis (94+/-9 vs. 91+/-7 micromol kg(-1) h(-1); NS), and (3) a approximately 25% rise in leucine oxidation (30+/-1 vs. 38+/-2 micromol kg(-1) h(-1), P<0.05), despite an approximately 25% decline (P<0.05) in leucine concentration.
Conclusions: In a model of mild, stress-induced protein catabolism, depletion of plasma glutamine per se may worsen branched chain amino acid and protein wasting.
Databáze: MEDLINE
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