The main goal of this project is to determine whether mitochondrial function in circulating cells is related to that measured in the muscle fibers of the same subjects.

Data from human and animal models strongly suggests that reduced tissue mitochondrial function can be an early marker for detection of dysfunctional metabolism. It is unclear if tissue mitochondrial dysfunction can be detected using less invasive methodology. In this project, the investigators plan to study mitochondrial bioenergetics in circulating cells and paired muscle biopsies in two metabolic disparate groups of women; healthy lean vs. overweight/obese with/without insulin resistant women of similar age. Women of similar age that are either healthy lean or overweight/obese with/without insulin resistance will be recruited to participate in one study that includes a blood draw and a muscle biopsy. Mitochondrial function in circulating blood cells and muscle tissue will be determined. The association between circulating blood cells and muscle tissue mitochondria respiration will be determined for the two groups combined, and differences between groups will also be investigated.

Inclusion Criteria:

• Women
• 25-35 years of age
• Either healthy lean (BMI<25) or insulin resistant and obese (BMI >30)

Exclusion Criteria:

• Medication that can affect study outcomes, as determined by the principal investigator, including anti-diabetic medication
• Chronic diseases, acute inflammation, chronic renal failure (glomerular filtration rate <45), or heart problems

Twenty (20) healthy lean and 20 insulin resistant and obese women, age 25-35 years.

Approximately 10 days following biopsy

Cross-sectional study with no intervention. Moderate risk study with one blood sample and one muscle biopsy.