Glucagon-like Peptide 1, Glucose Metabolism and Gastric Bypass (GLP-1)

September 8, 2025 updated by: The University of Texas Health Science Center at San Antonio

The Role of Glucagon Like Peptide-1 in Glucose Metabolism and Weight Loss Following Gastric Bypass Surgery

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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

80

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Texas
      • San Antonio, Texas, United States, 78207
        • Recruiting
        • Texas Diabetes Institute - University Health System
        • Contact:
        • Contact:
      • San Antonio, Texas, United States, 78229
        • Recruiting
        • South Texas Veterans Health Care System
        • Contact:
        • Principal Investigator:
          • Marzieh Salehi, MD
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

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 Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Non-Randomized
  • Interventional Model: Factorial Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
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
Drug: exendin-(9-39)
hyperglycemic clamp-meal tolerance test is designed to assess insulin secretion before and after meal ingestion
Other Names:
  • no other name for exendin-(9-39)
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
Drug: 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.
Other Names:
  • no other name for exendin-(9-39)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
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)
up to 1 year (10 sessions)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The University of Texas Health Science Center at San Antonio

Investigators

  • Principal Investigator: Marzieh Salehi, MD,MS, Marzieh Salehi

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

November 1, 2005

Primary Completion (Estimated)

August 1, 2026

Study Completion (Estimated)

August 1, 2027

Study Registration Dates

First Submitted

February 20, 2013

First Submitted That Met QC Criteria

March 1, 2013

First Posted (Estimated)

March 4, 2013

Study Record Updates

Last Update Posted (Estimated)

September 9, 2025

Last Update Submitted That Met QC Criteria

September 8, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HSC20180070H
  • DK083554 (Other Grant/Funding Number: NIDDK)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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