• DIABETIC SUBJECTS:

INCLUSION CRITERIA:

1. Type 2 diabetes mellitus as defined by:

   1. Fasting blood glucose greater than or equal to 126 mg/dL OR postprandial blood sugar greater than or equal to 200 mg/dL (either during OGTT at NIH or as previously documented on outside medical record).
   2. Since subjects may already have been started on treatment with hypoglycemic agents at the time of enrollment, they may have blood glucose levels in the impaired glucose tolerance range (fasting glucose 100-125 mg/dL and postprandial 140-199 mg/dL). This is a sign of adequately controlled diabetes, rather than an incorrect diagnosis of diabetes. Therefore, prior documentation (on outside medical records) of blood glucose values documenting diabetes will be acceptable if the subject has impaired glucose tolerance rather than overt diabetes according to screening results at NIH.
   3. Absence of insulin autoantibodies (in insulin na ve patients only)

   Or

2. Clinical diagnosis of type 1 diabetes mellitus (for Pilot Study only)

   And

3. Age 8-25 years at enrollment

EXCLUSION CRITERIA:

1. Normal OGTT at NIH (fasting blood glucose < 100 mg/dL AND 2 hour blood glucose < 140 mg/dL)
2. Significant comorbidity that, in the opinion of the investigators, will increase risk to the subject(specific obesity-related comorbidities are explicitly permitted, including hypertension, hyperlipidemia, obstructive sleep apnea and non-alcoholic steatohepatitis)
3. Positive urine pregnancy test
4. Psychiatric or cognitive disorder that will, in the opinion of the investigators, limit the subject's ability to comply with study procedures

NON-DIABETIC CONTROLS:

INCLUSION CRITERIA:

Two types of volunteers will be recruited:

1. Overweight and obese volunteers who will be BMI matched with study enrollees who have T2DM during analyses
2. Normal weight (BMI between 5th and 85th centiles for age) volunteers

EXCLUSION CRITERIA:

1. Diabetes
2. Significant comorbidity that, in the opinion of the investigators, will increase risk to the subject (specific obesity-related comorbidities are explicitly permitted, including hypertension, hyperlipidemia, obstructive sleep apnea and non-alcoholic steatohepatitis)
3. Current use of drugs that alter glucose metabolism (e.g. metformin)
4. Current use of prescription or non-prescription weight-loss drugs
5. Positive urine pregnancy test
6. Psychiatric or cognitive disorder that will, in the opinion of the investigators, limit the subject's ability to comply with study procedures