The disease diabetes mellitus is due to either destruction of the cells that produce insulin or a decrease in sensitivity of target cells to circulating insulin. How would this affect the level of glucose in the blood? Why?

Diabetes mellitus results from a deficiency in the amount of insulin released from the pancreas in response to glucose (type I) or from a decrease in the ability of muscle and fat cells to respond to insulin (type II). In both types, the regulation of blood glucose is impaired, leading to persistent hyperglycemia and numerous other possible complications in untreated patients such as tissue damage, raises the risk of heart-attack, kidney disease and vision deterioration. Type I diabetes is caused by an autoimmune process that destroys the insulin-producing B cells in the pancreas. Also called insulin-dependent diabetes, this form of the disease is generally responsive to insulin therapy. Most Americans with diabetes mellitus have type II, but the underlying cause of this form of the disease is not well understood.