title: Impact of glutamine supplementation on glucose homeostasis during and after exercise.
abstract: The interaction of glutamine availability and glucose homeostasis during and after exercise was investigated, measuring whole body glucose kinetics with [3-3H]glucose and net organ balances of glucose and amino acids (AA) during basal, exercise, and postexercise hyperinsulinemic-euglycemic clamp periods in six multicatheterized dogs. Dogs were studied twice in random treatment order: once with glutamine (12 micromol.kg(-1).min(-1); Gln) and once with saline (Con) infused intravenously during and after exercise. Plasma glucose fell by 7 mg/dl with exercise in Con (P < 0.05), but it did not fall with Gln. Gln further stimulated whole body glucose production and utilization an additional 24% above a normal exercise response (P < 0.05). Net hepatic uptake of glutamine and alanine was greater with Gln than Con during exercise (P < 0.05). Net hepatic glucose output was increased sevenfold during exercise with Gln (P < 0.05) but not with Con. Net hindlimb glucose uptake was increased similarly during exercise in both groups (P < 0.05). During the postexercise hyperinsulinemic-euglycemic period, glucose production decreased to near zero with Con, but it did not decrease below basal levels with Gln. Gln increased glucose utilization by 16% compared with Con after exercise (P < 0.05). Furthermore, net hindlimb glucose uptake in the postexercise period was increased approximately twofold vs. basal with Gln (P < 0.05) but not with Con. Net hepatic uptake of glutamine during the postexercise period was threefold greater for Gln than Con (P < 0.05). In conclusion, glutamine availability modulates glucose homeostasis during and after exercise, which may have implications for postexercise recovery.
authors.affiliation: Center for Designing Foods to Improve Nutrition, Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Soh
authors.initials: S
authors.lastname: Iwashita
authors.forename: Phillip
authors.initials: P
authors.lastname: Williams
authors.forename: Kareem
authors.initials: K
authors.lastname: Jabbour
authors.forename: Takeo
authors.initials: T
authors.lastname: Ueda
authors.forename: Hisamine
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Shawn
authors.initials: S
authors.lastname: Baier
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Flakoll
mesh_terms: D000596:Amino Acids / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D004285:Dogs; D005260:Female; D005947:Glucose / Q000493:pharmacokinetics*; D015309:Glucose Clamp Technique; D005973:Glutamine / Q000097:blood / Q000494:pharmacology*; D006706:Homeostasis / Q000187:drug effects* / Q000502:physiology*; D006946:Hyperinsulinism / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D014316:Tritium
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D007328:Insulin; D005973:Glutamine; D014316:Tritium; D005947:Glucose