Insulin-Mediated Glucose Uptake and Organ Perfusion Assessed by Total-Body PET During GIP and GLP-1 Infusion

Dynamic Whole-Body FDG and H₂¹⁵O PET-CT to Assess Insulin-Mediated Glucose Uptake and Organ Perfusion During GIP and GLP-1 Infusion in Healthy Individuals and Patients With Type 2 Diabetes

This study investigates how the naturally occurring gut hormones GIP and GLP-1 influence whole-body glucose uptake and organ perfusion in humans. Using a state-of-the-art total-body PET-CT scanner, the study measures dynamic uptake of the glucose analogue 18F-FDG and blood flow using H₂¹⁵O across multiple organs during controlled elevations of plasma glucose and endogenous insulin secretion.

The project consists of two sub-studies. Sub-study 1 includes healthy individuals who undergo three experimental visits with infusions of GIP, GLP-1, or saline (placebo) during a hyperglycemic clamp followed by FDG PET-CT scanning.

Sub-study 2 includes healthy individuals and participants with type 2 diabetes who undergo two experimental visits with saline followed by either GIP or GLP-1 during a hyperglycemic clamp, combined with repeated H₂¹⁵O PET-CT measurements of perfusion.

The primary aims are to quantify insulin-mediated skeletal muscle glucose uptake (sub-study 1) and skeletal muscle perfusion (sub-study 2). Secondary aims include assessment of glucose uptake and perfusion across adipose tissue, liver, and additional organs. The results will provide novel physiological insight into postprandial glucose metabolism and serve as reference data for future whole-body PET research.

Study Overview

• Status: Recruiting
• Conditions: Type 2 Diabetes; Healhty
• Intervention / Treatment: Drug: GIP; Drug: GLP-1; Other: Saline (0.9% Sodium Chloride)

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mathilde Borring Brogaard, Doctor; Phone Number: +4535454498; Email: mathilde.borring.brogaard@regionh.dk
• Study Contact Backup: Name: Per Cramon, Doctor; Email: Per.Cramon@regionh.dk

Study Locations

• Denmark
  • Copenhagen, Denmark, 2100
    • Recruiting
    • Copenhagen University Hospital - Rigshospitalet
    • Contact: Peter Hovind, Cheif doctor; Phone Number: +4535459824; Email: peter.hovind@regionh.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Sub-study 1 (Healthy individuals):

• Age 23-50 years
• BMI 20.0-26.9 kg/m²
• HbA1c < 42 mmol/mol
• Able to provide informed consent

Sub-study 2 - Participants with Type 2 Diabetes:

• Age 23-60 years
• Diagnosed with type 2 diabetes for ≥3 months
• HbA1c > 53 mmol/mol
• Treatment with metformin only
• Able to provide informed consent

Sub-study 2 - Healthy control participants:

• Age 23-64 years
• HbA1c < 42 mmol/mol
• Able to provide informed consent

Exclusion Criteria (applies to all participants unless otherwise specified):

• Anaemia (haemoglobin below normal range)
• ALT > 2× upper normal limit or any known hepatobiliary or gastrointestinal disorder
• Kidney disease (creatinine above normal range)
• Previous gastric or intestinal resection (except appendectomy or cholecystectomy) or major abdominal surgery (including bariatric surgery)
• For Sub-study 1: Type 1 or type 2 diabetes or HbA1c ≥ 42 mmol/mol
• Use of glucose-lowering medications other than metformin (Sub-study 2 only)
• Chronic obstructive pulmonary disease (Sub-study 2 only)
• Regular tobacco smoking or use of nicotine-containing products
• Claustrophobia
• Pregnancy, breastfeeding, or intention to become pregnant during the study period
• Initiation of special diets, major lifestyle changes, or weight loss > 5% within 3 months prior to or during the study
• Any medication or physical/psychological condition that may interfere with participation (per investigator judgement)
• Inability to speak or read Danish

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: GIP infusion	Drug: GIP; Intravenous infusion of glucose-dependent insulinotropic polypeptide (GIP) consisting of a priming dose of 18 pmol/kg/min for 10 minutes followed by a steady-state infusion of 6 pmol/kg/min during a hyperglycemic clamp. Used to stimulate endogenous insulin secretion and mimic postprandial physiology
Experimental: GLP-1 infusion	Drug: GLP-1; Intravenous infusion of glucagon-like peptide-1 (GLP-1) consisting of a priming dose of 4.5 pmol/kg/min for 10 minutes followed by a steady-state infusion of 1.5 pmol/kg/min during a hyperglycemic clamp. Used to stimulate endogenous insulin secretion and mimic postprandial physiology.
Experimental: Saline Placebo	Other: Saline (0.9% Sodium Chloride); Intravenous infusion of isotonic saline administered as placebo. In sub-study 1, saline serves as a control condition; in sub-study 2, saline is infused for 15 minutes prior to hormone infusion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metabolic Rate of FDG	MRFDG quantified using dynamic total-body 18F-FDG PET with 3-compartment kinetic modelling during infusion of GIP, GLP-1, or placebo.	75 minuts

Secondary Outcome Measures

Outcome Measure	Time Frame
Perfusion of skeletal muscle	75 min

Collaborators and Investigators

• Sponsor: Rigshospitalet, Denmark

Study record dates

Study Major Dates

• Study Start (Estimated): March 12, 2026
• Primary Completion (Estimated): March 12, 2027
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: January 28, 2026
• First Submitted That Met QC Criteria: February 4, 2026
• First Posted (Actual): February 9, 2026

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: February 4, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: IncretinPET
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 2; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Inorganic Chemicals; Chlorine Compounds; Sodium Compounds; Gastrointestinal Hormones; Glucagon-Like Peptides; Proglucagon; Chlorides; Hydrochloric Acid; Glucagon-Like Peptide 1; Sodium Chloride
• Other Study ID Numbers: H-25055805

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: No
• Studies a U.S. FDA-regulated device product: No