INFLUENCE OF GLUTAMINE-SUPPLEMENTED PARENTERAL-NUTRITION ON INTESTINAL AMINO-ACID-METABOLISM IN RATS AFTER SMALL-BOWEL RESECTION

Glutamine (Gln)-supplemented total parenteral nutrition (TPN) has been shown to improve mucosal adaptation after massive small bowel resecti on (SBR); however, its influences on intestinal amino acid metabolism remain unknown. In this study, intestinal amino acid Bur, circulating plasma aminogram, mucosal glutaminase activity and protein, and DNA co ntent were measured 7 days after massive SBR in rats receiving either standard (Std) or Gin-supplemented TPN. Sham-operated rats and rats fe d chow after enterectomy served as controls, The uptake of Gin and the release of citrulline (Cit) by the remaining intestine was significan tly decreased, with reduced mucosal glutaminase activity after SBR in the Chow and Std-TPN groups. Glutamine supplementation resulted in sig nificantly increased gut Gin uptake compared with Std-TPN (P < 0.01). Mucosal glutaminase activity, mucosal protein, and DNA content was als o increased by Gin; however, the gut release of Cit remained unchanged (P > 0.05). The subsequent decrease in circulating arginine (Arg) in the Gln-TPN group compared with the Std-TPN group (P < 0.05) was attri buted to an insufficient exogenous supply. These findings show that Gi n-supplemented TPN improves mucosal growth and gut Gin uptake after SB R. However, the intestinal production of Cit, which remained low in bo th TPN groups, may lead to an insufficiency of endogenous Arg synthesi s, Thus, both Gin and Arg may be essential amino acids after SBR.