title: Glycemic effects and safety of L-Glutamine supplementation with or without sitagliptin in type 2 diabetes patients-a randomized study.
abstract: OBJECTIVE
  L-glutamine is an efficacious glucagon-like peptide (GLP)-1 secretagogue in vitro. When administered with a meal, glutamine increases GLP-1 and insulin excursions and reduces postprandial glycaemia in type 2 diabetes patients. The aim of the study was to assess the efficacy and safety of daily glutamine supplementation with or without the dipeptidyl peptidase (DPP)-4 inhibitor sitagliptin in well-controlled type 2 diabetes patients.
  
  
  METHODS
  Type 2 diabetes patients treated with metformin (n = 13, 9 men) with baseline glycated hemoglobin (HbA1c) 7.1±0.3% (54±4 mmol/mol) received glutamine (15 g bd)+ sitagliptin (100 mg/d) or glutamine (15 g bd) + placebo for 4 weeks in a randomized crossover study.
  
  
  RESULTS
  HbA1c (P = 0.007) and fructosamine (P = 0.02) decreased modestly, without significant time-treatment interactions (both P = 0.4). Blood urea increased (P<0.001) without a significant time-treatment interaction (P = 0.8), but creatinine and estimated glomerular filtration rate (eGFR) were unchanged (P≥0.5). Red blood cells, hemoglobin, hematocrit, and albumin modestly decreased (P≤0.02), without significant time-treatment interactions (P≥0.4). Body weight and plasma electrolytes remained unchanged (P≥0.2).
  
  
  CONCLUSIONS
  Daily oral supplementation of glutamine with or without sitagliptin for 4 weeks decreased glycaemia in well-controlled type 2 diabetes patients, but was also associated with mild plasma volume expansion.
  
  
  BACKGROUND
  ClincalTrials.gov NCT00673894.
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia; Faculty of Medicine, UNSW (The University of New South Wales), Sydney, Australia.
authors.forename: Dorit
authors.initials: D
authors.lastname: Samocha-Bonet
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia; Faculty of Medicine, UNSW (The University of New South Wales), Sydney, Australia.
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Chisholm
authors.affiliation: Cambridge Institute of Medical Research and Department of Clinical Biochemistry, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Gribble
authors.affiliation: School of Mathematics and Statistics, UNSW (The University of New South Wales), Sydney, Australia.
authors.forename: Adelle C F
authors.initials: AC
authors.lastname: Coster
authors.affiliation: Disciplines of Genetic Medicine & Paediatrics and Child Health, University of Sydney, Sydney, Australia.
authors.forename: Kevin H
authors.initials: KH
authors.lastname: Carpenter
authors.affiliation: Faculty of Medicine, UNSW (The University of New South Wales), Sydney, Australia; Department of Chemical Pathology, St. Vincent's Hospital, Sydney, Australia.
authors.forename: Graham R D
authors.initials: GR
authors.lastname: Jones
authors.affiliation: NNF Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Panum Institute, Copenhagen, Denmark.
authors.forename: Jens J
authors.initials: JJ
authors.lastname: Holst
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia; Faculty of Medicine, UNSW (The University of New South Wales), Sydney, Australia; Department of Endocrinology and Diabetes Center, St. Vincent's Hospital, Sydney, Australia.
authors.forename: Jerry R
authors.initials: JR
authors.lastname: Greenfield
mesh_terms: D000284:Administration, Oral; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D005973:Glutamine / Q000008:administration & dosage* / Q000009:adverse effects* / Q000627:therapeutic use; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008687:Metformin / Q000008:administration & dosage / Q000627:therapeutic use; D008875:Middle Aged; D010953:Plasma Volume / Q000187:drug effects; D000068900:Sitagliptin Phosphate / Q000008:administration & dosage* / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D005973:Glutamine; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D008687:Metformin; D000068900:Sitagliptin Phosphate; C517652:hemoglobin A1c protein, human