Protective Effect of Methionine and Vitamin C on Hepatic Glucose Metabolism in ChlropyrifosExposed Male Wistar Rats

Chlorpyrifos exposure is associated with impairment in hepatic glucose metabolism. This study investigates the effect of methionine and/ or vitamin C on hepatic glucose metabolism in chlorpyrifos-exposed male Wistar rats. Twenty-five male Wistar rats (120-180g) were grouped into 5 as I-V. Group I (control) received sunflower oil (1ml/kg) while II-V were orally administered chlorpyrifos (6.8mg/kg) followed by methionine (100 mg/kg), vitamin C (200 mg/kg) and a combination of both to III, IV and V, respectively for 28 days. Plasma was obtained for acetylcholinesterase activity and liver function test (AST, ALT, and ALP) while the liver was obtained for determination of glycogen content, hexokinase activity, lactate dehydrogenase activity (LDH), and markers of oxidative stress (MDA, SOD, and catalase). Hepatic MDA level increased in II and decreased in III-V compared with control. Increased LDH activity was observed in II relative to control. Glycogen content and hexokinase activities were decreased in II relative to control while they were increased in V compared with II. Acetylcholinesterase activity decreased in II compared with control and increased in V compared with II. In conclusion, methionine and vitamin C prevented chlorpyrifos-induced hepatic glycogen depletion and hexokinase inhibition through a mechanism that involves prevention of lipid peroxidation and promotion of acetylcholinesterase activity.