title: Endogenous glutamine production in critically ill patients: the effect of exogenous glutamine supplementation.
abstract: BACKGROUND
  Glutamine rate of appearance (Ra) may be used as an estimate of endogenous glutamine production. Recently a technique employing a bolus injection of isotopically labeled glutamine was introduced, with the potential to allow for multiple assessments of the glutamine Ra over time in critically ill patients, who may not be as metabolically stable as healthy individuals. Here the technique was used to evaluate the endogenous glutamine production in critically ill patients in the fed state with and without exogenous glutamine supplementation intravenously.
  
  
  METHODS
  Mechanically ventilated patients (n = 11) in the intensive care unit (ICU) were studied on two consecutive days during continuous parenteral feeding. To allow the patients to be used as their own controls, they were randomized for the reference measurement during basal feeding without supplementation, before or after the supplementation period. Glutamine Ra was determined by a bolus injection of 13C-glutamine followed by a period of frequent sampling to establish the decay-curve for the glutamine tracer. Exogenous glutamine supplementation was given by intravenous infusion of a glutamine containing dipeptide, L-alanyl-L-glutamine, 0.28 g/kg during 20 hours.
  
  
  RESULTS
  A 14% increase of endogenous glutamine Ra was seen at the end of the intravenous supplementation period as compared to the basal measurements (P = 0.009).
  
  
  CONCLUSIONS
  The bolus injection technique to measure glutamine Ra to estimate the endogenous production of glutamine in critically ill patients was demonstrated to be useful for repetitive measurements. The hypothesized attenuation of endogenous glutamine production during L-alanyl-L-glutamine infusion given as a part of full nutrition was not seen.
authors.forename: Maiko
authors.initials: M
authors.lastname: Mori
authors.forename: Olav
authors.initials: O
authors.lastname: Rooyackers
authors.forename: Marie
authors.initials: M
authors.lastname: Smedberg
authors.forename: Inga
authors.initials: I
authors.lastname: Tjäder
authors.forename: Ake
authors.initials: A
authors.lastname: Norberg
authors.forename: Jan
authors.initials: J
authors.lastname: Wernerman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016638:Critical Illness / Q000628:therapy*; D019587:Dietary Supplements; D005260:Female; D005973:Glutamine / Q000008:administration & dosage* / Q000097:blood*; D006801:Humans; D007275:Injections, Intravenous; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D010288:Parenteral Nutrition / Q000639:trends; D010865:Pilot Projects; D012121:Respiration, Artificial / Q000639:trends; D016896:Treatment Outcome
chemical_list: D005973:Glutamine
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