Insulin Resistance: Causes and Metabolic Implications

ABSTRACT

Insulin is an anabolic hormone that plays key roles in glucose metabolism. Insulin resistance is a decreased biological response to normal concentration of circulating insulin. In insulin resistance; normal amounts of insulin are inadequate to produce a normal insulin response from fat; muscle and liver cells. Insulin resistance in fat cells results in hydrolysis of stored triglycerides; which elevates free fatty acids in the blood plasma. In muscles; it reduces glucose uptake; whereas in the liver; it reduces glucose storage with both effects serving to elevate blood glucose. High plasma levels of Insulin and glucose due to Insulin resistance often lead to metabolic syndrome and type 2 diabetes mellitus. The cause of the vast majority of cases of insulin resistance remains unknown. However; it is claimed that insulin resistance might be caused by a high carbohydrate diet. Studies have shown that glucosamine (often prescribed for joint problems) may cause Insulin resistance. It is also reported that insulin resistance occurrence in a population increased as sugar consumption and addition of high fructose corn syrup to diets increased. Physical inactivity and obesity have been implicated as factors; which aggravate insulin resistance. The presumption that a defect in specific gene may cause insulin resistance is still under investigation