Role of KATP Channel Loss in Type 2 Diabetes

Inclusion Criteria: * Lean-normoglycemic group (n=10): BMI ≥18.5 and \<25.0 kg/m², fasting plasma glucose concentration \<95 mg/dl, 2-hr oral glucose tolerance test plasma glucose concentration ≤140-mg/dl, and hemoglobin A1C (HbA1C) ≤5.6%. * Obesity-normoglycemic group (n=10): BMI ≥30 and \<50 kg/m², fasting plasma glucose concentration \<95 mg/dl, 2-hr oral glucose tolerance test plasma glucose concentration ≤140 mg/dl, and hemoglobin A1C (HbA1C) ≤5.6%. * Obesity-impaired fasting glucose group (n=10): BMI ≥30 and \<50 kg/m², fasting plasma glucose concentration 100-125 mg/dl, and 2-hr oral glucose tolerance test plasma glucose concentration \<200 mg/dl. * Obesity-type 2 diabetes group (n=10): BMI ≥30 and \<50 kg/m²; HbA1C 6.5-9.5%, fasting plasma glucose ≥126 mg/dl, 2-hr oral glucose tolerance test plasma glucose concentration ≥200 mg/dl and/or medical history of T2DM and currently using anti-diabetic medications. Exclusion Criteria: * Diabetes therapy with insulin at \>0.5 units/kg/day. * Any change in diabetes medication in previous 3 months. * Unstable weight (\>2% change during the last 2 months before entering the study). * Evidence of significant organ system dysfunction or disease other than obesity and T2D. * Regular use of tobacco products. * Excessive consumption of alcohol (≥3 drinks/day for men and ≥2 drinks/day for women). * Use of medications that are known to affect the study outcome measures (e.g., steroids, non-statin lipid-lowering medications) or increase the risk of study procedures (e.g., anticoagulants) and that cannot be temporarily discontinued for this study. * Anemia (Hemoglobin \<10.0 g/dL). * Pregnant or breastfeeding. * Unable or unwilling to follow the study protocol or for any reason the research team believes the volunteer is not an appropriate candidate for this study, including non-compliance with screening appointments or previous medical visits.