Type 2 is characterized by two problems. The first, as in Type 1, is a diminished ability of the pancreas to secrete insulin. The second issue is one of insulin resistance. In other words, the receptors on the cell wall that would normally open the door to the cell to let the glucose in when insulin 'knocks', stop 'listening' to the insulin. The cells 'resist' the signal that the circulating insulin is sending and the glucose is not transferred to the inside of the cell, resulting in an elevated blood glucose (hyperglycemia) and cellular 'starvation'. The elevated blood glucose, in turn, sends a signal to the pancreas telling it to secrete more insulin. The elevated insulin may somewhat override the insulin resistance resulting in more glucose entering the cells, but eventually the pancreas can become exhausted or 'burned out'.
Glucose toxicity results from chronic hyperglycemia. Glucose toxicity wreaks havoc on the entire body - especially the pancreas and its insulin-producing cells. A vicious cycle then ensues as the insulin-producing cells are damaged resulting in less insulin being produced.
