Background: The gastrointestinal tract is recognized as having importa
nt metabolic functions. This study examined gut glutathione (GSH) extr
action and the effect of supplemental oral glutamine (GLN) on gut GSW
fractional release. Methods: Healthy female Fisher-344 rats weighing a
pproximately 150 to 200 g were pair-fed chow and supplemented by gavag
e 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 bloo
d 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 i
nto why feeding via the gut rather than by the venous route is so impo
rtant. Supple mental oral GLN further enhances GLN extraction as well
as GSH fractional release in the gut.