Glutamine-enhanced enteral diet improves nitrogen balance without increasing portal ammonia

Following surgical stress the jejunum actively metabolizes endogenous glutamine, a non-essential amino acid, to produce alanine and ammonia, which augments substrate flow to the liver at a time when oral intake of nutrients is decreased. Oral glutamine supplementation theoretically may modify the response to injury. This study was designed to demonstrate the role of the jejunum in postinjury glutamine metabolism and to evaluate the influence of enteral glutamine supplements on nitrogen and ammonia metabolism after laparotomy and bowel resection in dogs. Oral glutamine in the presence of an intact small bowel significantly improved nitrogen balance (461 mg kg body-weight-1 day-1) compared with a control diet (-370 mg kg-1 day-1) (P less than 0.05, analysis of variance). Removal of the proximal small bowel prevented this beneficial effect of glutamine (-507 mg kg-1 day-1). Glutamine-supplemented and control diets were associated with similar portal ammonia concentrations throughout the study.