There are close links among hyperglycaemia, oxidative stress and diabetic complications. Glutamine (GLN) is an amino acid with immunomodulatory properties. The present study investigated the effect of dietary GLN on oxidative stress-relative gene expressions and tissue oxidative damage in diabetes. There were one normal control (NC) and two diabetic groups in the present study. Diabetes was induced by an intraperitoneal injection of nicotinamide followed by streptozotocin (STZ). Rats in the NC group were fed a regular chow diet. In the two diabetic groups, one group (diabetes mellitus, DM) was fed a common semi-purified diet while the other group received a diet in which part of the casein was replaced by GLN (DM-GLN). GLN provided 25 % of total amino acid N. The experimental groups were fed the respective diets for 8 weeks, and then the rats were killed for further analysis. The results showed that blood thioredoxin-interacting protein (Txnip) mRNA expression in the diabetic groups was higher than that in the NC group. Compared with the DM group, the DM-GLN group had lower glutamine fructose-6-phosphate transaminase 1, a receptor of advanced glycation end products, and Txnip gene expressions in blood mononuclear cells. The total antioxidant capacity was lower and antioxidant enzyme activities were altered by the diabetic condition. GLN supplementation increased antioxidant capacity and normalised antioxidant enzyme activities. Also, the renal nitrotyrosine level and Txnip mRNA expression were lower when GLN was administered. These results suggest that dietary GLN supplementation decreases oxidative stress-related gene expression, increases the antioxidant potential and may consequently attenuate renal oxidative damage in rats with STZ-induced diabetes.Key words: Glutamine: Diabetes: Thioredoxin-interacting protein: Glutamine fructose-6-phosphate transaminase 1: Nitrotyrosine Diabetes mellitus (DM) is a metabolic disorder characterised by hyperglycaemia, disturbance of macronutrients, and the development of micro-and macrovascular complications. Increasing evidence from both experimental and clinical studies suggests that there are close links among hyperglycaemia, oxidative stress and diabetic complications (1,2) . There are four main hypotheses about how hyperglycaemia causes diabetic complications: (1) increased polyol pathway flux; (2) increased hexosamine pathway flux; (3) activation of protein kinase C (PKC) isoforms; (4) increased advanced glycation end-product (AGE) formation. These metabolic pathways are major contributors to reactive oxygen species (ROS) overproduction and high oxidative stress during hyperglycaemia (2 -4) .Glutamine (GLN) is the most abundant free amino acid in the circulation. Several studies have demonstrated that GLN has immunomodulating properties and suppresses inflammatory responses (5,6) . GLN is required during catabolic processes to manifest optimal tissue responses to catabolism, inflammation and infection. It is considered an essential amino acid during certain dis...

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