Studies on the development of an insulin resistant rat model by chronic feeding of low magnesium high sucrose diet.

ABSTRACT

Magnesium deficiency and excess sucrose in the diet have been shown to play an important role in the development of insulin resistance. In the present study we have looked at the combined effect of a low magnesium high sucrose diet on basal glucose and insulin levels, erythrocyte insulin receptors and lipid profile in rats. For this purpose rats were divided into four groups and fed control, low magnesium, high sucrose and low magnesium high sucrose diets respectively for three months. The biochemical analysis showed a significant increase in blood glucose and triglyceride levels after one, two and three months of feeding in both the high sucrose and the low magnesium high sucrose groups, while rats fed a low magnesium diet showed a significant increase in blood glucose and triglyceride levels only after the second month. Insulin levels increased significantly in low magnesium, high sucrose and low magnesium high sucrose groups by the end of the study period. Compared to control rats, the binding of insulin to the erythrocyte insulin receptors was reduced significantly in the high sucrose and the low magnesium high sucrose groups. Cholesterol levels were found to increase significantly in the high sucrose group at the end of one month and three months of feeding. HDL-cholesterol decreased significantly in the low magnesium high sucrose group by the end of the study. Serum and RBC magnesium levels demonstrated a significant decrease in the low magnesium and the low magnesium high sucrose groups. The post heparin plasma lipoprotein lipase activity was decreased significantly in low magnesium, high sucrose and low magnesium high sucrose groups compared to control rats. These findings suggest that feeding a diet low in magnesium and high in sucrose causes insulin resistance in rats.