NCT07818707 · Joslin Diabetes Center
Post-Prandial Carbohydrate Metabolism in Individuals With and Without Post-Bariatric Surgery Hypoglycemia (PBH)
What this study is about
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.
View original scientific description
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.
Interventions
DRUG
Glucagon for Injection (Fresenius Kabi USA)
The investigators are assessing glucagon metabolism in individuals with and without PBH in fasting and post-prandial states.
DRUG
[6,6-2H2] glucose
The investigators are using a stable isotope glucose tracer to assess glucose metabolism in individuals with and without PBH in fasting and post-prandial states.
DRUG
[13C9, 15N1]-glucagon
The investigators are assessing the metabolism of glucagon in individuals with and without PBH in fasting and post-prandial states.
DRUG
[1-13C] glucose
The investigators are assessing the metabolism of glucose in individuals with and without PBH in fasting and post-prandial states.
DRUG
[2-13C] glucose
The investigators assessing the metabolism of glucose in individuals with and without PBH in fasting and post-prandial states.
Primary outcome measures
Between-group differences in iAUC for postprandial EGP
Time frame: During Visit 2, within 10 days of the baseline visit
Between-group differences in endogenous glucose production (EGP) in the postprandial state, as quantified by iAUC for postprandial EGP. These measurements will be taken at baseline and after mixed-meal consumption, specifically at minutes 10, 20, 30, 60, 90, 120, 150, and 180.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Age 18-70 years of age, inclusive, at screening.
- Willingness to provide informed consent and follow all study procedures, including attending all scheduled visits.
- Males or females at least 2 years following Roux-en-Y gastric bypass (RYGB)
- For patients recruited to PBH group: diagnosed with ongoing PBH, with documented episodes of hypoglycemia, and history of fulfillment of Whipple's triad.
Exclusion criteria
- Documented hypoglycemia occurring only in the fasting state (\>12 hours fast);
- Current diabetes, defined as hemoglobin A1c \>6.5% or use of diabetes medications, except for acarbose or miglitol;
- Chronic kidney disease stage 4 or 5 (including end-stage renal disease);
- Hepatic disease, including serum ALT or AST greater than 2 times the upper limit of normal; hepatic synthetic insufficiency as defined as serum albumin \< 3.0 g/dL; or serum bilirubin \> 2.0;
- Congestive heart failure, NYHA class II, III or IV;
- History of myocardial infarction, unstable angina or revascularization within the past 6 months.
- Two or more risk factors for coronary artery disease including diabetes, uncontrolled hypertension, uncontrolled hyperlipidemia, and active tobacco use.
- History of recurrent syncope (unrelated to hypoglycemia) or active diagnosis of a cardiac arrhythmia;
- Current administration of β-blocker therapy;
- History of a cerebrovascular accident;
- Seizure disorder (other than with suspect or documented hypoglycemia);
- Active treatment with long-acting (LAR) octreotide or pasireotide;
- Active malignancy, except basal cell or squamous cell skin cancers;
- Personal or family history of pheochromocytoma or disorder with increased risk of pheochromocytoma (MEN 2, neurofibromatosis, or Von Hippel-Lindau disease);
- Known insulinoma;
- Major surgical operation within 30 days prior to screening;
- Clinically significant anemia as defined as a hematocrit \< 33%;
- Bleeding disorder, treatment with warfarin, or platelet count \<50,000;
- Blood donation (1 pint of whole blood) within the past 2 months;
- Active alcohol abuse or substance abuse;
- Current administration of oral or parenteral corticosteroids;
- Pregnancy and/ or lactation: For persons of childbearing potential: there is a requirement for a negative urine pregnancy test before any procedures.
- Not enrolled in another study that uses an investigational drug for this condition.
Where
- Birmingham, Alabama
- Boston, Massachusetts
Collaborators
University of Alabama at Birmingham, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Sep 14, 2026 · Source of record for eligibility and locations