Monosodium Glutamate Induces Oxidative Stress and Affects Glucose Metabolism in the Kidney of Rats

Monosodium glutamate (MSG) is a widely used flavour enhancer with a number of adverse effects. Earlier studies have shown the induction of oxidative stress in some organs of experimental animals after chronic administration of MSG. Some reports have also shown some alterations in hepatic glucose metabolism as a result of MSG administration. In this study, we have tested the hypothesis that alteration in glucose metabolism following MSG administration might be a contributor to the changes in the markers of oxidative stress observed in the animals. Twenty four male Wistar rats were divided into two groups. MSG was orally administered to one group of rats at a dose of 4g/kg body weight for ten days while the other group received normal saline. MSG-treated rats showed a significant alteration (P<0.05) in a number of oxidative stress parameters and a significant (P<0.05) increase in the activity of glucose-6-Phosphatase (G6Pase), corroborating earlier observations. In addition, there was a decrease in the activity of glucose-6-phosphate dehydrogenase (G6PD) and a significantly (P<0.05) higher blood glucose and renal glucose concentration in MSG-treated rats. There was no change in renal glycogen concentration following MSG administration. The pattern of induction of oxidative stress and alteration of glucose metabolic enzymes in the animals is an indication that oxidative stress induced by MSG in the renal tissues of rats might be contributed by increased tissue glucose concentration resulting from enhanced renal gluconeogenesis.