Measurement of Glucose Metabolism in Humans: Effect of Recurrent Hypoglycemia on Hypothalamic GABA

Study Overview
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Brief Summary
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You are invited to participate in a study designed to investigate the effects of diabetes mellitus, high and low glucose, and high blood insulin on the brain. You were selected as a possible participant because you fit into one of the following categories. a) you are either healthy and competent, are not pregnant and you have no known medical disease and therefore your glucose metabolism will be typical of a normal person, or b) you have diabetes.

Detailed Description
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Glucose is a major fuel for most organs in the human body, particularly the brain. How and where the body uses glucose is regulated by a number of hormones, for instance insulin and glucagon. In a number of diseases, in particular diabetes mellitus, the glucose supply to the brain may be different than normal, which may be a cause for reduced glucose awareness. The purpose of this study is to determine the effects of altered glucose metabolism on the brain. For example, patients with long duration diabetes mellitus lose their ability to secrete the hormones necessary to protect them against hypoglycemia, which may be due to alterations in glucose availability to the human brain. To measure these effects, we will use intravenous infusions of glucose and insulin.

Official Title
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Measurement of Glucose Metabolism in Humans Using Magnetic Resonance at 7 Tesla: Effect of Recurrent Hypoglycemia on Hypothalamic GABA

Conditions
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Type 1 Diabetes, Healthy

Intervention / Treatment
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* Other: hypoglycemia (low blood sugar) and MRI


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: well controlled type 1 diabetes (hemoglobin A1c <7.5%) age 18-65 healthy controls Exclusion Criteria: history of stroke, seizures, neurosurgical procedures, or arrhythmias use of drugs that can alter GABA metabolism (such as benzodiazepines). Subjects must also meet requirements for a study in the magnet, which includes weight less than 300 lbs and the absence of metallic substances in their body.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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: Supportive Care
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: type 1 diabetes<br>type 1 diabetes >5 years duration | Other: hypoglycemia (low blood sugar) and MRI<br>* hypoglycemia (low blood sugar) and MRI<br>|
| Placebo Comparator: healthy controls<br> | Other: hypoglycemia (low blood sugar) and MRI<br>* hypoglycemia (low blood sugar) and MRI<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Euglycemic GABA level in hypothalamus using MRI | MRI measurement of GABA in the hypothalamus | Baseline to 2 month |