Investigating how neural and hormonal factors affect insulin secretion after gastric bypass surgery

Hormonal and Neural Control of Insulin Secretion Following Gastric Bypass Surgery

Early Phase 1 Interventional The University of Texas Health Science Center at San Antonio · NCT00992901

This study is trying to see how certain hormones and nerve signals affect insulin release in people who have had gastric bypass surgery, especially looking at those who experience low blood sugar compared to those who don’t and healthy individuals.

Quick facts

PhaseEarly Phase 1
Study typeInterventional
Enrollment160 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorThe University of Texas Health Science Center at San Antonio Academic / other
Locations2 sites (San Antonio, Texas and 1 other locations)
Trial IDNCT00992901 on ClinicalTrials.gov

What this trial studies

This research evaluates the role of neural and gastrointestinal (GI) hormones in insulin secretion among patients who have undergone Roux-en-Y gastric bypass (RYGB) surgery. It aims to understand how these factors contribute to improved glucose metabolism and the occurrence of hypoglycemia in RYGB patients. The study will compare insulin responses in hypoglycemic RYGB patients, asymptomatic RYGB patients, and healthy non-surgical controls. Various interventions, including GLP-1 and atropine, will be administered to assess their effects on islet cell function and responsiveness.

Who should consider this trial

Good fit: Ideal candidates include RYGB patients experiencing hypoglycemia and asymptomatic individuals who have undergone bariatric surgery.

Not a fit: Patients with active serious medical conditions, type 2 diabetes, or those who have had complications from surgery may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to better management strategies for insulin secretion and hypoglycemia in patients post-gastric bypass surgery.

How similar studies have performed: While the specific mechanisms of insulin secretion post-RYGB are still being explored, similar studies have shown promising results in understanding hormonal influences on glucose metabolism.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Hypoglycemic RYGB patients with documented blood glucose level \<50 mg/dl
* Asymptomatic individuals with bariatric surgery
* Healthy non-surgical patients with no personal history of diabetes
* Subjects must physically be able to come to our clinical research center at Cedars-Sinai Medical Center

Exclusion Criteria:

* Active heart, lung, liver, gastrointestinal or kidney disease; unable to give informed consent; pregnancy; uncontrolled high blood pressure or high cholesterol; significant anemia (hemoglobin \<11g/dL); prisoners or institutionalized individuals; type 2 diabetes melitis; development of any serious medical or psychiatric illness during recruitment or studies;
* RYGB patients will also be disqualified if they have gastric outlet obstruction or severe diarrhea
* Healthy non-surgical patients with personal history of diabetes

For administration of atropine, the following exclusions also apply:

* History of glaucoma
* Uncontrolled hypertension (any subjects with BP\>140/90 and history of dyslipidemia
* Taking any medication that might interact with atropine and cannot be stopped will be excluded from the study)
* Myasthenia gravis
* Brain pathology
* Enlarged prostate in men

Where this trial is running

San Antonio, Texas and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Post BariatricsurgeryHypoglycemiagastric bypass surgeryglucose toleranceInsulin response to meal ingestionGut hormone and neural response to meal ingestion
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.