Hypoglycemia is the term used to refer to lower than normal levels of blood sugar. This study will continue to research the causes of hypoglycemia.

Patients involved in the study will be admitted to the Clinical Center of the National Institutes of Health and undergo tests for evaluating blood sugar. Patients will be required to refrain from eating for a set period of time and will undergo blood tests for insulin levels and several other specific diagnostic tests related to insulin secretion. The patients will be under supervision and will be provided with appropriate medical and surgical attention as needed....

Study Description:

The purpose of this study is to gain knowledge and experience in the diagnosis and therapy of patients with fasting hypoglycemia due to diverse etiologies, such as insulinomas. Study subjects will be evaluated and treated for their particular condition according to standard care.

Objectives:

1. To understand the pathophysiology and various causes of hypoglycemia (e.g., insulinomas, MEN1, MEN2).
2. To identify new circulating biomarkers of insulinomas.
3. To create a repository of clinical data and samples for future research of insulinomas.

Endpoints: None

• INCLUSION CRITERIA:

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

1. Male, females ages >= 18.
2. Patients with documented fasting blood glucose below 55 mg/dl.

4. Patients with biochemical evidence for insulinoma or other pancreatic neuroendocrine tumors.

EXCLUSION CRITERIA:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Patients with significant cardiac disease will be excluded.
2. Subjects who are pregnant per self-report.
3. Medically unstable per the assessment of the PI.

Patients how are referred to us that have fasting hypoglycemia due to diverse etiologies.@@@@@@