PARENTERAL-NUTRITION MODIFIES GLUCOSE AND GLUTAMINE-METABOLISM IN RATISOLATED ENTEROCYTES

Background & Aims: After small bowel resection, parenteral nutrition i s often required to provide energy and nitrogen supplies and also to s timulate intestinal adaptation, despite the absence of glutamine in fo rmulas, The aim of this study was to investigate the effect of nutrien t supply route on fuel utilization by enterocytes. Methods: Rats recei ved an intravenous or intragastric continuous infusion of an all-in-on e glutamine free formula, Sham-operated control rats were orally fed a nd received the same protein-caloric supplies as the other two groups. On day 7, the rats were killed in the fed state, blood samples were c ollected, and the jejunoileum was removed, Enterocytes were isolated, Aliquots of cell suspensions were incubated (30 minutes at 37 degrees C) in the presence of [C-14]glucose and [C-14]glutamine (2 mmol/L). Su bstrate utilization was determined by measuring metabolites and CO2 ge nerated, Results: Intravenously fed rats showed mild hyperglycemia and marked hyperinsulinemia, Plasma glutamine levels were similar in the three groups. Intravenously fed rats showed a simultaneous increase in glutamine utilization and a decrease in glucose utilization compared with intragastrically fed and control rats, without parallel changes i n glutaminase and hexokinase activities, The basolateral glucose trans porter protein concentration was reduced in intravenously fed rat ente rocytes. Conclusions: The route of nutrient delivery influences fuel u tilization by enterocytes.