Clinical Research Directory

Post-Prandial Carbohydrate Metabolism in Individuals With and Without Post-Bariatric Surgery Hypoglycemia (PBH)

In this study, the investigators will determine (a) whether metabolism (secretion and turnover) of glucagon is altered in patients with PBH, (b) whether this is affected by a meal, (c) whether PBH affects the ability of the body to produce glucose (endogenous glucose production), and (d) whether PBH affects the amount of glycogen in the liver (storage form of glucose) when fasting and after a meal. The investigators will determine the effect of glucagon to raise glucose levels after a meal. To answer these questions, participants will receive an infusion of a stable (nonradioactive) isotope of glucose and glucagon, and a meal containing a stable isotope of glucose. Glycogen will be measured by magnetic resonance imaging (MRI) of the liver before and after the meal. This information will be used to develop computer models for the glucagon pump system.

Glucagon Dose-Response in Patients With Post-Bariatric Hypoglycemia

The purpose of the study is to determine how blood sugar levels in individuals with and without hypoglycemia after bariatric surgery respond to different doses of glucagon, a hormone that is usually present in your body that regulates blood sugar levels. In this study, there will be 4 visits to the clinical research center. In the first visit, medical history and physical exam will be performed, and blood samples will be taken to assess overall health. During visit 2, a continuous glucose monitor will be placed under the skin. (This may be combined with visit 1, depending on the schedule of visits.) In visit 3, we will test the effect of a total of 4 different doses of glucagon, in increasing doses. In visit 4, we will test the effect of a total of 3 doses of glucagon, in decreasing doses. For both visit 3 and 4, we will infuse labeled stable glucose to allow us to measure how much glucose the body is making, and will measure levels of hormones which regulate glucose, such as insulin and glucagon.