Exercise, Glucose Kinetics, and the Incretin Effect

Study Overview
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Brief Summary
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Human volunteers will be stratified by oral glucose tolerance status: normal glucose tolerant, impaired glucose tolerant, and type 2 diabetic. All subjects will undergo 4 experimental trials: [1] an oral glucose tolerance test (OGTT) combined with infused and ingested stable isotopes of glucose to assess glucose kinetics. [2] a 1 hour bout of cycling exercise at 50% of maximum power output, immediately followed by the same OGTT combined with stable isotope glucose tracers used in trial 1. [3] an isoglycemic clamp to match the plasma glucose profile measured in trial 1. [4] a 1 hour bout of cycling exercise at 50% of maximum power output, immediately followed by an isoglycemic clamp to match the plasma glucose profile measured in trial 2. Exercise-induced changes in oral glucose tolerance, glucose kinetics, insulin and glucagon secretion, and the incretin effect will be examined. The exercise responses will be compared between the subjects groups of different glucose tolerance status.

Official Title
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The Effects of Acute Exercise on Glucose Kinetics, Beta-cell Function and the Incretin Effect in Subjects Representative of the Whole Glucose Tolerance Continuum

Conditions
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Type 2 Diabetes

Intervention / Treatment
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* Behavioral: Exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age 18-60 years BMI 18-35 kg/m2 Exclusion Criteria: insulin dependency pregnancy presence or history of chronic cardiovascular, pulmonary, hepatic, renal, or hematological disease, or cancer contraindication to physical activity as assessed by ECG

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

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: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Resting Trial<br>a 1 hour period of rest immediately prior to OGTT or isoglycemic clamp | |
| Experimental: Exercise Trial<br>a 1 hour cycling exercise bout immediately prior to the OGTT or isoglycemic clamp | Behavioral: Exercise<br>* 1 hour of cycling at 50% of maximum power output<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glucose tolerance |  | Plasma glucose will be measured at 10 minute intervals during the OGTT (3 hours) immediately following the period of rest or exercise | 
| Incretin effect |  | Plasma insulin and C-peptide will be measured at 10 minute intervals during the OGTT (3 hours) and isoglycemic clamp (3 hours) immediately following the period of rest or exercise | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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GIP, Exercise, Physical activity, Type 2 diabetes, Obesity, Incretin effect, GLP-1, Insulin secretion, Glucagon, Beta-cell function, Disposition Index