Influence of N-acetylglutamine or glutamine infusion on plasma amino acid concentrations during the early phase of small-bowel adaptation in the dog.

Glutamine is a nonessential neutral amino acid that is widely consumed by the intestinal tract in catabolic states. We have followed up the plasma amino acid profile after extensive small-bowel resection in dogs receiving total parenteral nutrition (TPN) with or without glutamine (GLN) or N-acetylglutamine (aGLN) supplementation. Animals were divided into four groups according to the type of surgery (enterectomy or transection) and nutrition (TPN, TPN with aGLN, or TPN with GLN). Plasma GLN levels decreased in group I (enterectomy and TPN) on day 2 (p = .03) and significantly increased on postoperative days in groups III (enterectomy and TPN with aGLN) and IV (enterectomy and TPN with GLN). A significant increase of plasma GLN was observed in groups III and IV compared with group I on days 6 and 8 (p = .03 and p = .01). Plasma alanine decreased in groups with bowel resection, whereas no change was observed in the control group (transection) and the decrease of plasma alanine was significantly less pronounced in groups III and IV compared with group I. The increase of crypt depth and villous height was more pronounced in groups III and IV. These results suggest that GLN is a required substrate for mucosal growth and function, which could improve the intestinal adaptation encountered after enterectomy.