Multi-Tracer PET Quantitation of Skeletal Muscle Insulin Resistance in Type 2 Diabetes Mellitus

Inclusion Criteria:

• We will recruit eight normal weight (BMI 19 to 25 kg/m2), and eight overweight or obese (BMI 27 to 38 kg/m2), non-diabetic, healthy volunteers, who are between the ages of 30 to 55 years old. For scientific reasons it is crucial that the groups are age matched. Limiting the age range to a period of 25 years will help achieve this goal. Volunteers for these two groups must have a fasting glucose < 110 mg/dl; HbA1c < 6.0%; Hct > 34; ALT < 60; AST < 60; Alk phos < 150; sTSH < 8; Trig < 300; Chol < 250; systolic BP < 150; diastolic BP < 95; and be in good health. A medical history and physical exam will be conducted by a nurse practitioner or a medical doctor.

We will also recruit eight volunteers with type 2 DM; as the large majority of this patient population is overweight or obese, inclusion criteria will include BMI 27 to 38 kg/m2, and otherwise age- and gender-matched to the non-diabetic volunteers. At screening, HbA1c must be less than 8.5%. For scientific purposes we would like to study the volunteers with type 2 DM without the confounding effects of anti-diabetic medications, therefore, we propose to restrict recruitment to those who are either treated by diet and exercise alone, or to those who are on oral agents in the sulfonylurea class, metformin, or acarbose.

Exclusion Criteria:

• We will exclude volunteers taking thiazolidinediones as the washout period for this class is uncertain, and exclude those taking insulin as withdrawal likely would cause unacceptable levels of hyperglycemia.

Research volunteers with type 2 DM who are enrolled in the study and who are receiving oral diabetic agents (sulfonylureas, metformin or acarbose), will be instructed to withhold these medications for five days preceding both PET studies.

Previous difficulty with lidocaine (xylocaine) will be an exclusion. To be eligible for these studies, volunteers must be free of clinical evidence of cardiac, renal, hepatic, and vascular disease, or other major medical problems that would endanger the volunteers or compromise the scientific validity of the studies. Subjects with a history of myocardial infarction, proteinuria (defined as 1+ protein), alcohol or drug abuse, malignancy or neuromuscular disease will be excluded. Subjects who have gained or lost more than 3 kg during the past 3 months will be excluded. Because of the PET, MR, and DEXA scanning, all premenopausal women must have a negative pregnancy test within 24 hours prior to these procedures. To avoid radiation exposure of the infant, women who are currently breastfeeding will not be permitted to participate in this research study. Subjects will be excluded if they have a contraindication to MRI such as surgical or vascular implants, pregnancy, pacemaker, or claustrophobia. In subjects with a questionable history of metallic fragments, an X-ray of the suspected area of the body will be performed to rule such out.