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NCT Number: NCT01803451

Glucagon-like Peptide 1, Glucose Metabolism and Gastric Bypass

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.

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Key information

Conditions

Post-bariatric Surgery Glucose Metabolism Disorders Hypoglycemia Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Early Phase 1

Primary location

South Texas Veterans Health Care System, San Antonio, Texas, United States

About this study

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

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

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Exendin-(9-39)

Drug

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)

exendin -(9-39)

Drug

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)

Primary outcomes

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)

Study contacts

Contact information is provided by the study sponsor or research team.

Jennifer Foster, MSN

CONTACT

[email protected]

210-450-8696

Marzieh Salehi, MD MS

CONTACT

[email protected]

210-567-6691

Sponsors and collaborators

Lead sponsor

The University of Texas Health Science Center at San Antonio

Other

Registry information

Official study title

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

Acronym: GLP-1

Important dates

Study start: 2005
Primary completion: 2026
Study completion: 2027
First posted: Mar 4, 2013
Registry last updated: Sep 9, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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