Glutamine enhances gut glutathione production

Background: The gastrointestinal tract is recognized as having important metabolic functions. This study examined gut glutathione (GSH) extraction and the effect of supplemental oral glutamine (GLN) on gut GSH fractional release. Methods: Healthy female Fisher-344 rats weighing approximately 150 to 200 g were pair-fed chow and supplemented by gavage with 1 g/kg/d GLN or an isonitrogenous amount of Freamine (McGaw, St Louis, MO). Rats were sacrificed at 6 weeks. Arterial and portal blood was assayed for GLN and GSH content. The gut GLN and GSH extractions were calculated. Results: The gut GLN fractional uptake was increased by approximately 50%, and there was a near threefold increase in gut GSH fractional release in the GLN-supplemented group. Conclusions: The discovery of gut's role as a major producer of GSH may give insight into why feeding via the gut rather than by the venous route is so important. Supplemental oral GLN further enhances GLN extraction as well as GSH fractional release in the gut.