The maintenance of normal carbohydrate tolerance requires the coordinated interaction of glucose, insulin,and glucagon.In the postabsorptive state the inhibitory effect of insulin on hepatic glycogenolysis and gluconeogenesis is precisely balanced by the stimulatory effect of glucagon. This ensures an adequate supply of glucose to insulin-independent tissues such as the brain . By limiting lipolysis ,insulin also regulates the availability of free fatty acid. The rise in glucose that occurs after the ingestion of food stimulates the secretion of insulin and inhibits that of glucagon. These hormonal changes,as well as the modulatory effects of glucose itself, minimize the amount of glucose that must be metabilzed by insulin-sensitive tissues (such as muscle) by the enhancing hepatic glucose uptake and decreasing hepatic glucose release. At least in part because of insulin deficiency (relative or absolute),patients with diabetes mellitus have excessive hepatic release of glucose in both the postabsorptive states.
The maintenance of normal carbohydrate tolerance requires the coordinated interaction of glucose, insulin,and glucagon.In the postabsorptive state the inhibitory effect of insulin on hepatic glycogenolysis and gluconeogenesis is precisely balanced by the stimulatory effect of glucagon. This ensures an adequate supply of glucose to insulin-independent tissues such as the brain . By limiting lipolysis ,insulin also regulates the availability of free fatty acid. The rise in glucose that occurs after the ingestion of food stimulates the secretion of insulin and inhibits that of glucagon. These hormonal changes,as well as the modulatory effects of glucose itself, minimize the amount of glucose that must be metabilzed by insulin-sensitive tissues (such as muscle) by the enhancing hepatic glucose uptake and decreasing hepatic glucose release. At least in part because of insulin deficiency (relative or absolute),patients with diabetes mellitus have excessive hepatic release of glucose in both the postabsorptive states.
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