The Role of Endogenous GLP-1 (Glycolipoprotein) in Regulating Glucose Stimulated Brain Activity

Study Overview
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Brief Summary
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Our objective is to investigate neuro-anatomical correlates of the regulation of energy intake by means of functional MRI. Administration of glucose with and without lactisole and exendin as well as fructose is followed by functional brain MRI, and findings are correlated with serum GLP-1 levels as an endogenous satiety signal in humans.

Official Title
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The Role of Endogenous GLP-1 in Regulating Glucose Stimulated Brain Activity

Conditions
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Exploratory Behavior

Intervention / Treatment
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* Dietary Supplement: tap water
* Dietary Supplement: Single intragastric instillation of 75g Glucose in 300ml tap water via nasogastric tube
* Dietary Supplement: Single intragastric instillation of 75g Glucose in 300ml tap water with 450ppm lactisole
* Dietary Supplement: 25g Fructose in 300ml tap water
* Dietary Supplement: 75g glucose in 300ml tap water with 600pmol/kg/min exendin 9-39
* Dietary Supplement: 300ml tap water with 450ppm lactisole


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: right-handed healthy males, no drugs, non-smoking Exclusion Criteria: drug abuse, smoker, left-handed, claustrophobia

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: 300ml tap water<br>Single intragastric instillation of 300ml tap water via nasogastric tube | Dietary Supplement: tap water<br> <br> |
| Active Comparator: Glucose<br>Single intragastric instillation of 75g Glucose in 300ml tap water via nasogastric tube | Dietary Supplement: Single intragastric instillation of 75g Glucose in 300ml tap water via nasogastric tube<br> <br> |
| Active Comparator: Glucose plus Lactisole<br>Single intragastric instillation of 75g Glucose in 300ml tap water with 450ppm lactisole | Dietary Supplement: Single intragastric instillation of 75g Glucose in 300ml tap water with 450ppm lactisole<br> <br> |
| Active Comparator: Fructose<br>Single intragastric instillation of 25g Fructose in 300ml tap water via nasogastric tube | Dietary Supplement: 25g Fructose in 300ml tap water<br> <br> |
| Active Comparator: Glucose and Exendin<br>Single intragastric instillation of 75g glucose in 300ml tap water with 600pmol/kg/min exendin 9-39 | Dietary Supplement: 75g glucose in 300ml tap water with 600pmol/kg/min exendin 9-39<br> <br> |
| Sham Comparator: tap water, lactisole<br>Single intragastric instillation of 300ml tap water with 450ppm lactisole | Dietary Supplement: 300ml tap water with 450ppm lactisole<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional magnetic resonance imaging (fMRI) in healthy volunteers while they performed a working memory task: changes in cerebral blood flow and blood hormones from baseline to treatment | Whole brain analysis with a cluster-level threshold was followed by an a priori defined region of interest analysis of the dorsolateral prefrontal cortex including a cluster-level threshold and family-wise error adjustment for multiple comparisons. | changes from baseline to one hour after treatment |