Starvation and endotoxin act independently and synergistically to coordinate hepatic glutamine transport
Fischer, C.P.; Bode, B.P.; Souba, W.W.
Journal of Trauma 40(5): 688-92; Discussion 692-3
1996
ISSN/ISBN: 0022-5282 PMID: 8614065 Document Number: 460596
Objective: Because hepatic glutamine transport is markedly enhanced during critical illness, we tested the hypothesis that nutrient starvation and endotoxemia act coordinately to augment transport activity. Design: Fed or starved (48 hours) rats received Escherichia coli endotoxin (LPS, 10 mg/kg of body weight, intraperitoneally) or saline before hepatocyte isolation for measurement of glutamine transport. Materials and Methods: Hepatocytes were isolated from fed or fasted rats 4 hours after LPS treatment. (3H)glutamine uptake was measured and normalized to cellular protein. Data (mean +- standard deviation, three separate determinations) were analyzed by Student's t test and analysis of variance. Main Results: Starvation induced a 1.6-fold increase in glutamine transport, while LPS treatment of fed rats increased transport activity 2.6-fold. Treatment of fasted animals with LPS induced a sixfold increase in glutamine transport. Kinetically, this effect in endotoxemic starved rats was mediated by both an increase in System N V-max and the induction of a high affinity System A amino acid carrier which transports glutamine. Conclusions: Starvation and endotoxemia regulate hepatocyte glutamine transport independently and synergistically. This hepatic response provides glutamine and other amino acids to support key metabolic pathways in the liver during critical illness.