Recruiting
Early Phase 1

Observational Study

Sponsor:

The University of Texas Health Science Center at San Antonio

Code:

NCT00992901

Conditions

Post Bariatricsurgery

Hypoglycemia

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Accepted

Interventions

Exendin-(9-39)

Atropine

GLP-1 and GIP

Study Details

Brief summary:

RYGB (roux-en-y gastric bypass) has been reported to reverse type 2 diabetes (T2DM) immediately after surgery before any significant weight loss. In addition, a growing number of patients have been recognized with life-threatening hyperinsulinemic hypoglycemia several years following their surgery. While the mechanisms by which RYGB improves glucose metabolism or alters islet cell function in patients after RYGB are not understood, recent studies suggest that increased secretion of GI hormones, primarily glucagon-like peptide 1 (GLP-1), as well as alteration in neural activity may contribute to enhanced insulin secretion in general, and to a greater extent in patients with hypoglycemia. The proposed research is designed to address the role of RYGB on insulin secretion by evaluating the contribution of stimulatory factors (neural and GI hormone) on islet cell function and the islet cell responsiveness to the physiologic stimulatory factors, in RYGB patients with and without hypoglycemia and non-operated controls.

Conditions

Post Bariatricsurgery

Hypoglycemia

Study ID

NCT00992901

Start date

Oct, 2009

Status verified date

Sep, 2025

Completion date

Aug, 2027

Anticipated

Primary completion date

Aug, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Accepted

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

Study Design

Enrollment

160 participants

Anticipated

Allocation

Non randomized

Intervention Model

Crossover

Primary purpose

Other

Interventions and Outcome Measures

Arms

experimental: Exendin-(9-39)

To evaluate the role of GLP-1 signaling in glucose tolerance and insulin secretion

experimental: atropine

To evaluate the effect of neural activation on insulin secretion and glucose metabolism

experimental: GLP-1 and GIP

to evaluate the beta-cell sensitivity to different doses of exogenous gut hormones

Interventions

Exendin-(9-39)

A physiological study to evaluate the role of GLP-1 signaling in glucose tolerance and insulin secretion

Atropine

A physiological study to evaluate the effect of neural activation on insulin secretion and glucose metabolism

GLP-1 and GIP

A physiological study to evaluate the beta-cell sensitivity to different doses of exogenous gut hormones

Primary outcome measure

  • Gut hormones and neural signaling contribution to insulin secretion rate and glucose tolerance [ Time Frame: Each study of the protocol is conducted up to seven hours with data collected at intervals specific to the individual study procedure. ]

Central Contacts and Locations

Central contacts

Marzieh Salehi, MD MS

210-567-6691salehi@uthscsa.edu

Jennifer Foster, MSN

210-450-8696fosterj6@uthscsa.edu

Locations

Texas Diabetes Institute - University Health System

Recruiting

San Antonio, Texas, United States, 78207

Contacts

Jennifer Foster, MSN

210-450-8696fosterj6@uthscsa.edu

Marzieh Salehi, MD, MS

210-567-6691salehi@uthscsa.edu

Principal Investigator:

Marzieh Salehi

South Texas Veterans Health Care System

Recruiting

San Antonio, Texas, United States, 78229

Contacts

Marzieh Salehi

210-567-6691salehi@uthscsa.edu

Jennifer Foster, MSN

210-450-8696fosterj6@uthscsa.edu

Principal Investigator:

Marzieh Salehi, MD, MS

More Information

Sponsor

The University of Texas Health Science Center at San Antonio

Last update posted

Sep 9, 2025

Last verified

Sep, 2025

Keywords

  • gastric bypass surgery
  • glucose tolerance
  • Insulin response to meal ingestion
  • Gut hormone and neural response to meal ingestion

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by The University of Texas Health Science Center at San Antonio on 2025-09-09.