Glucagon Suppression by Hyperglycemia in the Presence and Absence of Amino Acid Infusion

February 11, 2026 updated by: Adrian Vella, Mayo Clinic
This study is being done to better understand how amino acids alter the release of glucagon and insulin compared to glucose alone in health and disease.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

T2DM and prediabetes are characterized by abnormal post-prandial suppression of glucagon, which contributes to postprandial hyperglycemia by increasing endogenous glucose production (EGP). In rodents, altered glucagon signaling changes α-cell function and mass - an effect mediated by changes in circulating AA concentrations. Are the elevated concentrations of branched-chain AA and other AA metabolites in T2DM a cause or an effect of global α-cell dysfunction? To measure glucagon secretion, as well as glucagon action, we have developed a population model of glucagon kinetics allowing us to deconvolve secretion from glucagon concentrations in a manner similar to Van Cauter's model for insulin secretion from C-peptide. This enables better characterization of α-cell function in humans. In addition to our novel methodology, we can characterize α-cell responsiveness to a graded glucose infusion, by quantifying (G50) - the change in glucose concentration necessary to suppress glucagon secretion by 50%. These experiments will determine if the glucagon secretion in response to AA differs in obese individuals with T2DM from that observed in obese individuals without T2DM.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

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

Study Locations

  • United States
    • Minnesota
      • Rochester, Minnesota, United States, 55905
        • Mayo Clinic Rochester

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

25 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria - Obese Subjects with Type 2 Diabetes:

  • HbA1c ≤ 8.5% (type 2 diabetic subjects).
  • HbA1c ≤ 6.5% (obese and lean subjects).
  • BMI ≥ 28 Kg/M^2 (Obese subjects with and without type 2 diabetes).
  • BMI ≤ 25 Kg/M^2 (Lean subjects without type 2 diabetes).
  • Use of sulfonylureas or metformin only (type 2 diabetec subjects).
  • For female subjects: negative pregnancy test at the time of enrollment or study.
  • No history of prior upper abdominal surgery such as adjustable gastric banding, pyloroplasty and vagotomy.
  • No active systemic illness or malignancy.
  • No symptomatic macrovascular or microvascular disease.
  • No contraindications to MRI (e.g., metal implants, claustrophobia).
  • Hematocrit > 35%.
  • TSH > 0.4 or < 5.5.
  • Consumption of < 2 alcohol drinks per day or < 14 per week or a negative AUDIT questionnaire.

Exclusion Criteria - Obese Subjects with Type 2 Diabetes:

  • HbA1c ³ 8.5%
  • BMI ≤ 28 Kg/M2
  • Use of insulin or agents other than sulfonylureas or metformin.
  • For female subjects: positive pregnancy test at the time of enrollment or study
  • History of prior upper abdominal surgery such as adjustable gastric banding, pyloroplasty and vagotomy.
  • Active systemic illness or malignancy.
  • Symptomatic macrovascular or microvascular disease.
  • Contraindications to MRI (e.g., metal implants, claustrophobia).
  • Hematocrit < 35%
  • TSH < 0.4 or > 5.5.
  • Consumption of > 2 alcohol drinks per day or > 14 per week or a positive AUDIT questionnaire.

Inclusion Criteria - Obese Subjects without Type 2 Diabetes:

  • BMI ≥ 28 Kg/M2.
  • > 5% liver fat content, as determined by MRI using the proton density fat fraction (PDFF) technique.

Exclusion Criteria - Obese Subjects without Type 2 Diabetes:

  • HbA1c ≥ 6.5%
  • BMI ≤ 28 Kg/M2
  • Use of any glucose-lowering agents including metformin or sulfonylureas.
  • For female subjects: positive pregnancy test at the time of enrollment or study
  • History of prior upper abdominal surgery such as adjustable gastric banding, pyloroplasty and vagotomy.
  • Active systemic illness or malignancy.
  • Symptomatic macrovascular or microvascular disease.
  • Contraindications to MRI (e.g., metal implants, claustrophobia).
  • Hematocrit < 35%
  • TSH < 0.4 or > 5.5.
  • Consumption of > 2 alcohol drinks per day or > 14 per week or a positive AUDIT questionnaire.

Inclusion Criteria - Lean subjects without Diabetes:

- BMI ≤ 25 Kg/M^2).

Exclusion Criteria - Lean Subjects without Diabetes:

  • HbA1c ≥ 6.5%.
  • BMI ≥ 25 Kg/M^2.
  • Use of any glucose-lowering agents including metformin or sulfonylureas.
  • For female subjects: positive pregnancy test at the time of enrollment or study.
  • History of prior upper abdominal surgery such as adjustable gastric banding, pyloroplasty and vagotomy.
  • Active systemic illness or malignancy.
  • Symptomatic macrovascular or microvascular disease.
  • Contraindications to MRI (e.g., metal implants, claustrophobia).
  • Hematocrit < 35%.
  • TSH < 0.4 or > 5.5.
  • Consumption of > 2 alcohol drinks per day or > 14 per week or a positive AUDIT questionnaire.
  • Liver fat content ≥ 5% as determined by MRI using the proton density fat fraction (PDFF) technique.

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Healthy Adults, Obese Adults, Adults with Type 2 diabetes: Saline and Glucose
Study visit: Subjects will receive a caffeine free, standardized evening meal and remain fasting overnight. An IV infusion of saline and glucose (50%) will be given the next morning and continue until the end of study. Blood draws will be collected frequently from the IV line to monitor blood glucose levels.
Drug: Dextrose
Intravenous graded glucose infusion using 50% dextrose will commence at 1mg/kg/min and increase to 2 (0900), 4 (1000) and 8mg/kg/min (1100) every 60 minutes
Experimental: Healthy Adults, Obese Adults, Adults with Type 2 diabetes: Amino Acid and Glucose
Study visit: Subjects will receive a caffeine free, standardized evening meal and remain fasting overnight. An IV infusion of glucose (50%) will be given the next morning together with an IV infusion of Clinisol 15% (an amino acid mixture) will be given the next morning and continue until the end of study. Blood draws will be collected frequently from the IV line to monitor blood glucose levels.
Drug: Dextrose
Intravenous graded glucose infusion using 50% dextrose will commence at 1mg/kg/min and increase to 2 (0900), 4 (1000) and 8mg/kg/min (1100) every 60 minutes
Drug: Clinisol 15%
Intravenous infusion 0.003ml/kg/min infused from 0 to 240 minutes
Other Names:
  • Amino Acid Mixture

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Glucagon Suppression (G50) caused by amino acids vs. saline
Time Frame: 240 minutes of study
concentration of glucose necessary to suppress glucagon by 50%
240 minutes of study

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Glucagon suppression (G50) is greater in people with T2DM
Time Frame: 240 minutes of study
concentration of glucose necessary to suppress glucagon by 50%
240 minutes of study
glucagon suppression (G50) is greater in obese compared to lean people without T2DM
Time Frame: 240 minutes of study
concentration of glucose necessary to suppress glucagon by 50%
240 minutes of study

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Mayo Clinic

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Adrian Vella, MD, Mayo Clinic

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.

Helpful Links

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 30, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 22, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 22, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 3, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 11, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 22-000306
  • R01DK116231 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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