The Effects of Bariatric Surgeries on Glucose Metabolism

September 8, 2025 updated by: The University of Texas Health Science Center at San Antonio
The purpose of this study is learn the effect of gastric bypass surgery and sleeve gastrectomy on glucose metabolism mediated by neural and hormonal factors initiated after eating.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The purpose of this study is to determine the weight-independent effects of gastric bypass surgery and sleeve gastrectomy surgery on islet cell response after meal ingestion as mediated by hormonal and neural components of the gut. It will also address the differences between the two procedures.

Such information will be critical for the development of novel approaches for treatment of diabetes as well as improvement of glycemic effects of gastric bypass and sleeve gastrectomy in patients with partial diabetes remission or relapse after complete remission.

Study Type

Interventional

Enrollment (Estimated)

200

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

  • 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 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 mellitis; development of any serious medical or psychiatric illness during recruitment or studies;
  • RYGB patients will 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 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: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Exendin-(9-39)
To evaluate the role of GLP-1 on glucose metabolism and insulin secretin after glucose and protein ingestion.
Drug: Exendin-(9-39)
A physiological study to evaluate the role of GLP-1 on glucose metabolism and insulin secretin after glucose and protein ingestion.
Other Names:
  • no other name for Exendin-(9-39)
Experimental: Atropine
to evaluate the effect of neural activation on insulin secretion and glucose metabolism
Drug: Atropine
A physiological study to evaluate the effect of neural activation on insulin secretion and glucose metabolism.
Other Names:
  • Atropine sulfate

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Insulin levels measured after nutrient ingestion
Time Frame: Each study in the protocol is conducted up to seven hours with data collected at intervals specific to the individual study procedure.
Each study in the protocol is conducted up to seven hours with data collected at intervals specific to the individual study procedure.

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

Collaborators

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

  • Principal Investigator: Marzieh Salehi, MD, MS, The University of Texas Health Science Center at San Antonio

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

July 1, 2015

Primary Completion (Estimated)

August 1, 2026

Study Completion (Estimated)

August 1, 2027

Study Registration Dates

First Submitted

October 22, 2015

First Submitted That Met QC Criteria

July 5, 2016

First Posted (Estimated)

July 6, 2016

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

  • 20180070H
  • 1R01DK105379-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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