Contribution of Hyperinsulinemia vs. Hyperglycemia to Insulin Resistance in Type 1 Diabetes and Maturity Onset Diabetes of the Young, Type 2 (MODY2)

Inclusion Criteria: Inclusion criteria for all subjects: \- BMI 19-28 kg/m\^2 Additional inclusion criteria for T1DM subjects: * Age 13-51 * T1DM duration 1-20 years * HbA1c 5.9-8.0% Additional inclusion criteria for MODY2 subjects: * age 13-51 * positive GCK genetic sequencing * HbA1c 5.9-8.0% Additional inclusion criteria for control subjects: * age 18-5.1 * HbA1c \< 5.5% Exclusion Criteria: Exclusion criteria for all subjects: * severe hypoglycemia (\>= 1 episode in the past 3 months or diagnosis of hypoglycemia unawareness) * diabetes comorbidities (\>= 1 trip to emergency department for poor glucose control in the past 6 months, New York Heart Association Class II-IV cardiac functional status, systolic blood pressure \> 140 and diastolic blood pressure \> 100 mmHg, fasting triglycerides \> 400 mg/dL, liver transaminases \> 2 times the upper limit of normal, renal transplantation or serum creatinine \> 1.5 mg/dL) * confounding medications (any systemic glucocorticoid, any antipsychotic, atenolol, metoprolol, propranolol, niacin, any thiazide diuretic, any oral contraceptive pill with \> 35 mcg ethinyl estradiol, growth hormone, any immunosuppressant, any anti-hypertensive, any-antilipidemic) * pregnancy * Tanner stage \< 5 Additional exclusion criteria for T1DM subjects * any diabetes medication except insulin * fasting c-peptide \> 0.7 ng/mL