the concentration of glucose in the blood, which is regulated by the pancreatic hormones insulin and glucagon. Glucose is an important source of energy for the body, particularly the brain. The normal level of blood sugar for humans, measured 12 hours after the last meal, generally ranges between 70 and 110 mg glucose per deciliter of blood. Abnormally high or low levels (see hyperglycemia; hypoglycemia) may indicate any of several disease states.