Protective effect of methionine supplementation on arsenic-induced alteration of glucose homeostasis

Short term exposure of arsenic produces carbohydrate depletion and hypoglycemia. Dietary deficiency of methionine causes impaired biotransformation of arsenic which has been attributed to the pathogenesis of different diseases induced by arsenic. Accordingly, the effects of methionine supplementation on the altered glucose homeostasis induced by arsenic were studied. Arsenic (as sodium arsenite) treatment (i.p) of male Wistar rats (weighing 80–100 g) at a dose of 5.55 mg kg−1 body weight (equivalent to 35% LD50) per day for a period of 21 days caused a significant diminution in blood glucose level and fall in liver glycogen and pyruvic acid contents. The free amino acid nitrogen content of liver was elevated while that of kidney was decreased after arsenic treatment. Transaminase activities in liver and kidney were not significantly altered except that glutamate-pyruvate transaminase activity of kidney decreased significantly after arsenic treatment. Methionine supplementation reversed the above changes except decreased liver glycogen due to arsenic treatment. It may be suggested that hypoglycemia with associated decreased glycolytic activity induced by arsenic treatment at the present dose and duration can be partially counteracted by dietary methionine supplementation.