WHAT IS TOLBUTAMIDE TOLERANCE TEST (TTT)?
There are primarily three types of hypoglycemia: one type that involves an insulin-secreting tumour of the pancreas known as “insulinoma;” one that that is the result of hyperactive islet cells; and a third type that is a result of liver disease. Insulinomas secrete disproportionately high levels of insulin in response to blood glucose levels, causing frequent hypoglycemic episodes. Insulinoma can be diagnosed through this indirect test that administers intravenous tolbutamide, a sulfonylurea that stimulates the pancreas to produce insulin. When administered to a person with insulinoma, there is an exaggerated response, causing abnormally rapid and high insulin levels and abnormally prolonged hypoglycemic response.