RESUMO
We investigated the in vitro and in vivo effects of arginine (Arg) on thiobarbituric acid-reactive substances (TBA-RS) and on the activities of catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) in renal tissues of rats. We also studied the influence of antioxidants (α-tocopherol plus ascorbic acid) and nitric oxide synthase inhibitor NG -nitro-l-arginine methyl ester (l-NAME) on the effects elicited by Arg. Results showed that Arg in vitro (1.5 mM) decreased SOD activity and increased the levels of TBA-RS in the renal medulla. Acute administration of Arg [0.8 g/kg, intraperitoneal injection] decreased CAT activity, increased SOD activity and TBA-RS levels in the renal medulla, and decreased CAT activity in the renal cortex of rats. Most results were prevented by antioxidants and/or l-NAME. Data indicate that Arg causes an oxidative imbalance in the renal tissues studied; however, in the presence of antioxidants and l-NAME, some of these alterations in oxidative stress were prevented.