Browsing by Author "Kruger, Annalie"

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    Pre-exercise glutamine supplementation could prevent decreases in postexercise serum glutamine following a single bout of intensive exercise
    (2001) Strauss, Johannes A. de W.; Myburgh, Kathryn H.; Kruger, Annalie; Smith, Carine; Robson, Paula J.
    ENGLISH ABSTRACT: The objective is to determine if glutamine supplementation prior to exercise would cause an increase in serum glutamine concentration, as opposed to supplementation during exercise or in the post-exercise period. The subjects were fourteen female athletes of the local athletic club who volunteered to participate in the study. Design. This was a single-blind cross-over design. A single dose of 5 g L-glutamine, dissolved in 250 ml of a sugar-free orange drink, or a placebo, was given 45 min­ utes before the VO₂max test. Blood samples were col­ lected before supplementation, 45 minutes after supplementation, immediately after the VO₂max test, and 45 minutes into the recovery period. Blood samples were analysed for serum glutamine concentrations, using an enzymatic method with standard reagents (Glutamine / Glutamate Statpack, Sigma Bio Science™). Haematological variables were analysed by means of a Coulter Counter and a differential white blood cell (WBC) count was obtained from a stained (Leishman's stain) blood film. Results. The mean ± standard error of the mean (±SEM) age, mass, height and VO₂max of the subjects were 19.6 ± 0.4 years, 56.6 ± 1.6 kg, 168.6 ± 1.6 cm and 56.1 ± 1.4 ml/kg/min respectively. During the placebo trial the glutamine concentrations, when adjusted for haemoconcentration, decreased from the resting and pre-exercise concentrations of 675 ± 39 µmol/I and 652 ± 45 µmol/I respectively, to 499 ± 38 µmol/I immediately after exercise (P < 0.01). During the recovery period, glutamine concentrations (606 ± 44 µmol/I) returned to levels close to the resting and pre-exercise levels (P > 0.05). During the glutamine trial, pre-exercise concen­ trations of glutamine were raised from 725 ± 30 µmol/I to 1 252 ± 31 µmol/1 (P < 0.01). This increased level of glu­ tamine was maintained throughout the rest of the proto­ col. Following exercise, an expected increase in the absolute WBC count {almost doubled) was observed in both the placebo and glutamine trials (P < 0.01). No other differences in the absolute WBC and WBC-sub­ population counts were observed between trials. Conclusion. We conclude that glutamine supplementa­ tion before exercise could increase serum glutamine concentrations and may thus prevent the fall in glutamine observed during intensive exercise. This may influence WBC function, but has no effect on WBC concentrations.