Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise

Appl Physiol Nutr Metab. 2006 Oct;31(5):518-29. doi: 10.1139/h06-028.

Abstract

We examined the effect of a post-exercise oral carbohydrate (CHO, 1 g.kg(-1).h(-1)) and essential amino acid (EAA, 9.25 g) solution containing glutamine (0.3 g/kg BW; GLN trial) versus an isoenergetic CHO-EAA solution without glutamine (control, CON trial) on muscle glycogen resynthesis and whole-body protein turnover following 90 min of cycling at 65% VO2 peak. Over the course of 3 h of recovery, muscle biopsies were taken to measure glycogen resynthesis and mixed muscle protein synthesis (MPS), by incorporation of [ring-2H5] phenylalanine. Infusion of [1-13C] leucine was used to measure whole-body protein turnover. Exercise resulted in a significant decrease in muscle glycogen (p < 0.05) with similar declines in each trial. Glycogen resynthesis following 3 h of recovery indicated no difference in total accumulation or rate of repletion. Leucine oxidation increased 2.5 fold (p < 0.05) during exercise, returned to resting levels immediately post-exercise,and was again elevated at 3 h post-exercise (p < 0.05). Leucine flux, an index of whole-body protein breakdown rate, was reduced during exercise, but increased to resting levels immediately post-exercise, and was further increased at 3 h post-exercise (p < 0.05), but only during the CON trial. Exercise resulted in a marked suppression of whole-body protein synthesis (50% of rest; p < 0.05), which was restored post-exercise; however, the addition of glutamine did not affect whole-body protein synthesis post-exercise. The rate of MPS was not different between trials. The addition of glutamine to a CHO + EAA beverage had no effect on post-exercise muscle glycogen resynthesis or muscle protein synthesis, but may suppress a rise in whole-body proteolysis during the later stages of recovery.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amino Acids / blood
  • Amino Acids, Essential / administration & dosage*
  • Beverages
  • Biopsy, Needle
  • Blood Glucose / analysis
  • Dietary Carbohydrates / administration & dosage*
  • Exercise / physiology*
  • Glutamine / administration & dosage*
  • Glycogen / analysis
  • Glycogen / biosynthesis
  • Humans
  • Insulin / blood
  • Kinetics
  • Male
  • Muscle Proteins / biosynthesis*
  • Muscle, Skeletal / chemistry
  • Muscle, Skeletal / metabolism
  • Oxygen Consumption
  • Proteins / metabolism
  • Sports / physiology*

Substances

  • Amino Acids
  • Amino Acids, Essential
  • Blood Glucose
  • Dietary Carbohydrates
  • Insulin
  • Muscle Proteins
  • Proteins
  • Glutamine
  • Glycogen