Recruiting
Early Phase 1

Gastric Bypass

Sponsor:

The University of Texas Health Science Center at San Antonio

Code:

NCT01803451

Conditions

Post-bariatric Surgery

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Accepted

Interventions

exendin-(9-39)

exendin -(9-39)

Study Details

Brief summary:

The overall goal of this project is to understand the mechanisms by which gastric bypass surgery improves glucose metabolism.

The central hypothesis guiding this project is that the reconfiguration of intestinal transit with the Roux-en-Y will increase the release of insulinotropic GI hormones, termed incretins that improve insulin secretion and glucose metabolism. The study is divided into three specific aims.

1. To determine the role of incretin hormones on insulin secretion in patients with gastric bypass surgery using intravenous-oral hyperglycemic clamp.
2. To compare incretin effect and glucose tolerance among patient who suffer from hypoglycemia after RYGB and asymptomatic surgical and non-surgical individuals.
3. To quantify the contribution of GLP-1 to incretin effect enhancement following surgery.

Conditions

Post-bariatric Surgery

Study ID

NCT01803451

Start date

Nov, 2005

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:

  • age 18-65
  • healthy control without diabetes or active organ disease
  • Individuals with bariatric surgery
  • recurrent hypoglycemia post gastric bypass

Exclusion Criteria:

  • pregnancy
  • significant anemia
  • diabetes currently unless pre-op for bariatric surgery procedure
  • GI obstruction

Study Design

Enrollment

80 participants

Anticipated

Allocation

Non randomized

Intervention Model

Factorial

Primary purpose

Other

Interventions and Outcome Measures

Arms

experimental: hyperglycemic clamp-Meal tolerance test

these studies are to evaluate the effect of exendin-9 on insulin secretion before and after meal ingestion in patients after bariatric surgeries compared to non-surgical controls

experimental: Labeled meal tolerance test

The effect of GLP-1 receptor blockade on glucose tolerance and glucose kinetics are evaluated in the group patients with bariatric surgery vs. nonsurgical using exendin-9-39 infusion during one of the the 2-day dual tracer studies of meal tolerance test

Interventions

exendin-(9-39)

hyperglycemic clamp-meal tolerance test is designed to assess insulin secretion before and after meal ingestion

exendin -(9-39)

2-day meal tolerance tests with labeled oral and IV glucose using exendin-(9-39) infusion are designed to evaluate the role of GLP-1 signaling on glucose tolerance and glucose kinetics.

Primary outcome measure

  • The investigator measure glucose, islet and GI hormonal levels in response to meal ingestion as a composite measure and the percentage of contribution of GLP-1 contribution to postprandial insulin levels will also be calculated [ Time Frame: up to 1 year (10 sessions) ]

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

South Texas Veterans Health Care System

Recruiting

San Antonio, Texas, United States, 78229

Contacts

Marzieh Salehi, MD MS

210-567-6691salehi@uthscsa.edu

Jennifer Foster

210-450-8696fosterj6@uthscsa.edu

Principal Investigator:

Marzieh Salehi, MD

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
  • glucose metabolism
  • hypoglycemia

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.