Relationship Between Insulin Resistance and Diabetes

What is the relationship between insulin resistance and diabetes?

Type 2 diabetes is the type of diabetes that occurs later in life. Insulin resistance precedes the development of type 2 diabetes, sometimes by years. In individuals who will ultimately develop type 2 diabetes, it is believed that blood glucose and insulin levels are normal for many years; then at some point in time, insulin resistance develops.

At this point, there is often an association of high insulin levels, central obesity, cholesterol abnormalities, and /or high blood pressure (hypertension). When this constellation of disease processes occur, it is know as the metabolic syndrome.

One of the actions of insulin is to cause the cells of the body, particularly the muscle and fat cells, to remove and use glucose from the blood. This is one way in which insulin controls the level of glucose in blood. Insulin has this effect on the cells by binding to insulin receptors on the surface of the cells. You can think of it as insulin "knocking" on the doors of muscle and fat cells. The cells hear the knock, open up, and let glucose in to be used by the cell. With insulin resistance, the muscles don't hear the knock as well (they are resistant), and the pancreas is notified that it needs to make more insulin, which increases the level of insulin in the blood and causes a louder knock.

The resistance of the cells continues to increase over time. As long as the pancreas is able to produce enough insulin to overcome this resistance, blood glucose levels remain normal. When the pancreas can no longer produce enough insulin, the blood glucose levels begin to rise, initially after meals when glucose levels are at their highest and more insulin is needed, but eventually in the fasting state too. At this point, type 2 diabetes is present.

Source : medicinenet.com