Healthy, Obesity, Type 2 Diabetes
Conditions
Brief summary
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.
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.
Interventions
DRUGDextrose
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
DRUGClinisol 15%
Intravenous infusion 0.003ml/kg/min infused from 0 to 240 minutes
Sponsors
Mayo Clinic
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
25 Years to 65 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Glucagon Suppression (G50) caused by amino acids vs. saline | 240 minutes of study | concentration of glucose necessary to suppress glucagon by 50% |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Glucagon suppression (G50) is greater in people with T2DM | 240 minutes of study | concentration of glucose necessary to suppress glucagon by 50% |
| glucagon suppression (G50) is greater in obese compared to lean people without T2DM | 240 minutes of study | concentration of glucose necessary to suppress glucagon by 50% |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORAdrian Vella, MD
Mayo Clinic
Outcome results
None listed