Glutamine abstracts
Author Dechelotte, P; Darmaun, D; Rongier, M; Hecketsweiler, B; Rigal, O; Desjeux, J F
Institution Institut Nationale de la Sante et de la Recherche Medicale Unite 290, Hopital Saint-Lazare, Paris, France.
Title Absorption and metabolic effects of enterally administered glutamine in humans.
AMERICAN JOURNAL OF PHYSIOLOGY. vol. 260, no. 5 Pt 1 (1991 May): G677-82.
Abstract To assess absorption and metabolic effects of enterally delivered glutamine, a total of 10 healthy subjects received perfusions of natural L-glutamine at graded infusion rates (ranging from 0 to 126 mmol/h; n = 2-8 subjects at each rate) along with a nonabsorbable marker (polyethylene glycol) through a double-lumen nasojejunal tube. Perfusions were administered after an overnight fast during three consecutive 1- or 2.5-h periods and in a randomized order. In eight subjects, continuous intravenous infusion of D-[6,6-2H2]glucose, L-[1-13C]leucine, and L-[15N]alanine was simultaneously performed. Glutamine was nearly quantitatively absorbed over the 30-cm study segment; estimated Km and Vmax of glutamine absorption were 2.48 and 2.32 mmol/min over the 30-cm study segment. Enteral glutamine administration induced 1) a dose-dependent increase in plasma glutamine level; 2) a rise in the plasma level and appearance rate (Ra) of alanine (from 191 +/- 42 to 213 +/- 51 mumols.kg-1.h-1, P less than 0.05, for 0 and 46.8-mmol/h glutamine infusion rates, respectively) and in plasma levels of glutamate, citrulline, aspartate, and urea; 3) a decline in plasma free fatty acid and glycerol levels; and 4) no change in leucine or glucose Ra. We conclude that glutamine is efficiently absorbed by human jejunum in vivo and may directly inhibit lipolysis, whereas it neither affects proteolysis nor glucose production in healthy postabsorptive humans.
Candow, D G; Chilibeck, P D; Burke, D G; Davison, K S; Smith-Palmer, T
Institution College of Kinesiology, University of Saskatchewan, Saskatoon, Canada.
Effect of glutamine supplementation combined with resistance training in young adults.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY. vol. 86, no. 2 (2001 Dec): 142-9.
Abstract The purpose of this study was to assess the effect of oral glutamine supplementation combined with resistance training in young adults. A group of 31 subjects, aged 18-24 years, were randomly allocated to groups (double blind) to receive either glutamine (0.9 g x kg lean tissue mass(-1) x day(-1); n = 17) or a placebo (0.9 g maltodextrin x kg lean tissue mass(-1) x day(-1); n = 14 during 6 weeks of total body resistance training. Exercises were performed for four to five sets of 6-12 repetitions at intensities ranging from 60% to 90% 1 repetition maximum (1 RM). Before and after training, measurements were taken of 1 RM squat and bench press strength, peak knee extension torque (using an isokinetic dynamometer), lean tissue mass (dual energy X-ray absorptiometry) and muscle protein degradation (urinary 3-methylhistidine by high performance liquid chromatography). Repeated measures ANOVA showed that strength, torque, lean tissue mass and 3-methylhistidine increased with training (P < 0.05), with no significant difference between groups. Both groups increased their 1 RM squat by approximately 30% and 1 RM bench press by approximately 14%. The glutamine group showed increases of 6% for knee extension torque, 2% for lean tissue mass and 41% for urinary levels of 3-methylhistidine. The placebo group increased knee extension torque by 5%, lean tissue mass by 1.7% and 3-methylhistidine by 56%. We conclude that glutamine supplementation during resistance training has no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults.
Krzywkowski, K; Petersen, E W; Ostrowski, K; Kristensen, J H; Boza, J; Pedersen, B K
Institution Copenhagen Muscle Research Centre and Department of Infectious Diseases, Rigshospitalet, 2200 Copenhagen N, Denmark.
Effect of glutamine supplementation on exercise-induced changes in lymphocyte function.
Am J Physiol Cell Physiol. vol. 281, no. 4 (2001 Oct): C1259-65.
Journal Info Abbreviation: Am J Physiol Cell Physiol.
The purpose of this study was to investigate the possible role of glutamine in exercise-induced impairment of lymphocyte function. Ten male athletes participated in a randomized, placebo-controlled, double-blind crossover study. Each athlete performed bicycle exercise for 2 h at 75% of maximum O(2) consumption on 2 separate days. Glutamine or placebo supplements were given orally during and up to 2 h postexercise. The trial induced postexercise neutrocytosis that lasted at least 2 h. The total lymphocyte count increased by the end of exercise due to increase of both CD3(+)TCR alpha beta(+) and CD3(+)TCR gamma delta(+) T cells as well as CD3(-)CD16(+)CD56(+) natural killer (NK) cells. Concentrations of CD8(+) and CD4(+) T cells lacking CD28 and CD95 on their surface increased more than those of cells expressing these receptors. Within the CD4(+) cells, only CD45RA(-) memory cells, but not CD45RA(+) naive cells, increased in response to exercise. Most lymphocyte subpopulations decreased 2 h after exercise. Glutamine supplementation abolished the postexercise decline in plasma glutamine concentration but had no effect on lymphocyte trafficking, NK and lymphokine-activated killer cell activities, T cell proliferation, catecholamines, growth hormone, insulin, or glucose. Neutrocytosis was less pronounced in the glutamine-supplemented group, but it is unlikely that this finding is of any clinical significance. This study does not support the idea that glutamine plays a mechanistic role in exercise-induced immune changes.
Svanberg, E; Moller-Loswick, A C; Matthews, D E; Korner, U; Lundholm, K
Institution Department of Surgery, Sahlgrenska University Hospital, University of Goteborg, Goteborg, Sweden.
The effect of glutamine on protein balance and amino acid flux across arm and leg tissues in healthy volunteers.
CLINICAL PHYSIOLOGY. vol. 21, no. 4 (2001 Jul): 478-89.
BACKGROUND: Glutamine is important in nitrogen transportation and the physiological control of acid-base regulation. In addition, it has been assumed that glutamine regulates protein balance in skeletal muscles based on findings in both experimental and clinical studies. However, little information on glutamine and its effect on protein dynamics in normal individuals is available. Therefore, the aim of this study was to evaluate whether glutamine improves protein balance and uptake of various indispensable amino acids across peripheral tissue in healthy individuals. MATERIAL AND METHODS: Standard primed constant infusions of L-[ring-2H5]phenylalanine and [ring 3,3-2H2]tyrosine (2 micromol kg(-1) h(-1)) were performed after overnight fast in five healthy male volunteers before and during infusions of a standard and a glutamine/tyrosine enriched amino acid solution. Flux measurements of amino acids (AA) including 3-methylhistidine, glucose, lactate and free fatty acids (FFA) were performed across arm and leg tissues. RESULTS: Infusion of the standard AA solution (0.2 g N kg(-1) day(-1)) increased the net uptake of individual amino acids, but provision of the enriched solution (0.4 g N kg(-1) day(-1)) with increased amounts of glutamine and tyrosine seemed to compete unfavourably with the net uptake of other key amino acids as methionine and phenylalanine, which are indispensable in muscles for protein synthesis. Increased flux of amino acids across peripheral tissues did not influence on flux of glucose, free fatty acid and lactate. CONCLUSIONS: Glutamine provision did neither stimulate protein synthesis nor attenuate breakdown of either globular or myofibrillar proteins in skeletal muscles of healthy volunteers.