Damage to the body cells that make and use insulin that’s caused by high blood sugar levels. Glucotoxicity may be partly responsible for the insulin resistance and impaired insulin secretion seen in Type 2 diabetes.
Over 50 years ago, researchers showed that infusing large doses of glucose into healthy animals damaged their pancreatic islets (the tissue where insulin is produced) and caused permanent hyperglycemia (high blood sugar). Since that time, a number of studies have elaborated on this observation. It appears that high blood sugar levels can impair the release of insulin from the pancreas and that, in some cases, this impairment is permanent.
There is also evidence that chronic high blood sugar can contribute to insulin resistance, a condition in which extra insulin is required for glucose to move from the bloodstream into body cells.
Lowering blood sugar levels in people with Type 2 diabetes has been shown to reverse glucotoxicity and improve both insulin secretion and insulin resistance.