Comparative effect of intravenously or intragastrically administered glutamine on small intestinal function of the rat.

Effect of glutamine supplementation to parenteral nutrition on small intestinal function was evaluated in malnourished rats as well as normal rats. Animals were administered the solution supplemented with glutamine at 20% of total amino acids either intravenously or intragastrically for seven days. Intragastrically fed rats gained more weight than parenterally fed rats. In malnourished rats, whose small intestinal weight was decreased to 60% by feeding protein-free diet for four weeks or by fasting for seven days, small intestinal weight was further decreased by intravenous infusion but was maintained at the pre-infusion level by intragastric infusion. The intragastric administration of glutamine increased small intestinal weight and mucosal brush border enzyme activities of sucrase, leucine aminopeptidase and alkaline phosphatase, showing the beneficial effect of intragastrically administered glutamine to maintain small intestinal function. In parenteral nutrition, however, it seems that more than 20% supplementation of glutamine relative to total amino acids might be necessary to mitigate intestinal atrophy.