Final answer:
The insulin tolerance test evaluates an individual's insulin regulation: a drop with recovery in normal individuals, persistent hypoglycemia in Type I diabetes, inadequate response in Type II diabetes, and hypoglycemia in insulinoma. The glucagon tolerance test distinguishes whether hyperglycemia is due to defective insulin receptors or excessive insulin antagonists in diabetes.
Step-by-step explanation:
The insulin tolerance test (ITT) is a diagnostic tool used to assess an individual's ability to tolerate insulin and determine if their diabetes mellitus can be treated with insulin. In a normal individual, the administration of insulin would cause a drop in blood glucose levels, which would then be corrected by the body's own insulin release and glucose regulation system. In an individual with Type I diabetes (Insulin Dependent Diabetes Mellitus or IDDM), hypoglycemia is seen relative to the baseline, indicating that the pancreas is not secreting sufficient insulin. With Type II diabetes, characterized by insulin resistance, there may be an initial decrease in blood glucose levels, but the hyperglycemia persists, suggesting defective insulin receptors. For someone with an insulinoma, a tumor of the pancreas, there would be signs of hypoglycemia due to the excess secretion of insulin by the tumor.
The glucagon tolerance test helps further delineate the type of diabetes by assessing whether hyperglycemia is due to defective insulin receptors (indicating Type II diabetes) or due to excessive insulin antagonists. A positive glucose tolerance test (GTT) necessitates the ITT and Glucagon Tolerance Test (GuTT) to understand the specific type of diabetes and tailor the treatment effectively.