Insulin and Insulin Pulses During Fasting

Fasting hyperglycemia contributes disproportionately to nonenzymatic glycosylation and the microvascular complications of type 2 diabetes. However, little is known about the regulation of glucose concentrations in the fasting state relative to what is known about the postprandial state. The proposed experiment is part of a series of experiments designed to establish how glucagon and insulin interact with their receptors to control fasting glucose in health and in prediabetes.

Inclusion Criteria: * people with normal or impaired fasting glucose and normal or impaired glucose tolerance Exclusion Criteria: 1. HbA1c \> 6.5% 2. BMI ≥ 35 Kg/M2 3. Use of any glucose-lowering agents including metformin or sulfonylureas. 4. For female subjects: positive pregnancy test at the time of enrollment or study 5. History of prior upper abdominal surgery such as adjustable gastric banding, pyloroplasty and vagotomy. 6. Active systemic illness or malignancy. 7. Symptomatic macrovascular or microvascular disease. 8. Hematocrit \< 35%