Modulation of the flux patterns in carbohydrate metabolism in the livers of streptozoticin-induced diabetic rats by dietary caloric restriction

Carbohydrate metabolism is impaired in diabetes. The resultant hyperglycemia could cause tremendous changes in the metabolic activities of the liver. We therefore designed this study to investigate the effects of caloric restriction, which has been shown to improve blood glucose homeostasis, on carbohydrate metabolism in the livers of non-diabetic and streptozotocin-induced diabetic rats. Forty male Wistar rats were divided into two groups of caloric restricted (CR) and ad libitum (AL) fed rats. The caloric restricted animals were subjected to 30% caloric restriction. Feeding experiments were conducted for 9 weeks before the induction of diabetes in 50% of the groups. Caloric restriction was found to significantly decrease glycogen ( p < 0.001), hepatic glucose ( p < 0.01), phosphofructokinase ( p < 0.05), glucokinase ( p < 0.05), aldose reductase ( p < 0.05), and sorbitol dehydrogenase ( p < 0.05) and significantly increase hexokinase ( p < 0.001), glucose-6-phosphate dehydrogenase ( p < 0.05), and glucose-6-phosphatase activities ( p < 0.05) in diabetic and non-diabetic rats. From our results, it is suggested that alteration of the metabolic pathways involved in glucose metabolism in the liver could be one of the various ways in which CR attenuates hyperglycemic effects in diabetes.