Influence of oral glutamine and glucose on markers of oxidative stress in a paraquat rat model

SummaryBackground & aimsl-glutamine (l-Gln) is involved in several metabolic processes, and is classified as an essential amino acid in demanding metabolic conditions. The amino acids Gln, cysteine and glycine are the precursors of the tripeptide glutathione synthesis, which is present in cells mainly in the reduced form, one of the most important endogeneous antioxidant defense front. Considering that Gln, as glucose (Gluc), can be used as oxidative fuel molecules by the cells, the aim of this work was to investigate the Gln and Gluc influence on reduced glutathione content and oxidative damage, induced by paraquat.MethodsGlutathione content and oxidative damage were monitored by the formation of thiolate anions and tiobarbituric acid reactive substances, respectively. Paraquat, Gln and Gluc were given in 30 mg/kg body weight (BW), 1.0 M and 4.0 g/kg BW, respectively.ResultsGln was effective by increasing (∼40%) plasma glutathione levels under oxidative stress and decreasing (∼16%) TBARS levels in the hepatic tissue, while Gluc had a non-significant effect. On the other hand, in renal tissue upon oxidative stress TBARS levels were increased by Gln (∼55%) and Gluc (∼47%) inducing tissue damage.ConclusionsIn this work, we have shown in vivo, i.e. in the presence of all metabolic interactions, an organ-specific effect of substrate administration, the Gln optimized plasma glutathione, protecting the hepatic tissue against oxidative damages. The same effect was not observed for renal tissue.