Glutamine does not increase ammonia in systemically drained small bowel transplants

Glutamine (Gln) enhances small bowel function and ameliorates acute injury, but its metabolism generates portal ammonia (NH4), which normally is detoxified by the liver. Its beneficial use in small bowel transplantation (SBTx) therefore, may be offset by hyperammonemia, since such grafts may be systemically drained. We tested the hypothesis that oral glutamine supplementation increases plasma NH4 in rats with systemically drained SBTx. Lewis rats with isologous SBTx had plasma NH4 and Gln assayed during isonitrogenous, isocaloric Gln dietary supplementation and were compared to controls. Plasma NH4 levels were higher in the SBTx group during all dietary manipulations, consistent with previous studies. A Gln-deficient diet (0%) caused plasma Gln levels to fall in both experimental and control animals, but had no consistent effect on NH4 levels. With Gln supplementation (12.5 and 25% of total protein) Gln levels returned to baseline but again, plasma NH4 levels did not significantly change. We conclude that oral glutamine supplementation given in an isonitrogenous manner does not increase ammonia beyond that which is usually seen in animals with systemically drained SBTx. This suggests that Gln-enriched diets are not specifically contraindicated in patients with systemically drained SBTx and may be beneficial.