Effect of oral glutamine supplementation on human neutrophil lipopolysaccharide-stimulated degranulation following prolonged exercise

Recent studies have shown that neutrophils can utilize glutamine and that g lutamine supplementation can improve neutrophil function in postoperative a nd burn patients. The present study investigated the influence of oral glut amine supplementation on stimulated neutrophil degranulation and oxidative burst activity following prolonged exercise. Subjects, 7 well-trained men, reported to the laboratory following an overnight fast and cycled for 2 hrs at 60% VO(2)max on two occasions a week apart. They were randomly assigned to either a glutamine or placebo treatment. For both trials, subjects cons umed a sugar-free lemon drink at 15-min intervals until 90 minutes, then a lemon flavored glutamine drink (GLN) or sugar-free lemon drink (PLA) was co nsumed at 15-min intervals for the remaining exercise and the 2-hr recovery period. Venous blood samples were taken pre-, during, and postexercise. Gl utamine supplementation had no effect on the magnitude of postexercise leuk ocytosis, the plasma elastase concentration following exercise (which incre ased in both trials), or the plasma elastase release in response to bacteri al stimulation (which fell in both trials). Neutrophil function assessed by oxidative burst activity of isolated cells did not change following exerci se in either trial. These findings therefore suggest that the fall in plasm a glutamine concentration does not account for the decrease in neutrophil f unction (degranulation response) following prolonged exercise.