Intact Primary Mitochondrial Function in Myotubes Established from Women with PCOS

Context: Polycystic ovary syndrome (PCOS) affects 5-8% of fertile women and is often accompanied by insulin resistance, leading to increased risk of developing type 2 diabetes. Skeletal muscle from insulin-resistant PCOS subjects display reduced expression of nuclear encoded genes involved in mitochondrial oxidative metabolism. Objective: We aimed to investigate whether there was a primary mitochondrial dysfunction or difference in mitochondria content that might contribute to the in vivo detected insulin resistance. Design: The ATP synthesis with and without ATP use and the mitochondrial mass was determined in mitochondria isolated from myotubes established from PCOS subjects and control subjects. Patients: Myotubes were established from eight insulin-resistant PCOS subjects (verified by euglycemic hyperinsulinemic clamp) and eight healthy weight-and age-matched controls. Results: Mitochondrial mass and measurable mitochondrial ATP synthesis, with and without ATP use, were not different between PCOS subjects and control subjects. Conclusion: We found no evidence for a primary impaired mitochondrial function or content in myotubes established from PCOS subjects, and our results suggest that reduced expression of oxidative genes in PCOS subjects is an adaptive trait. (J Clin Endocrinol Metab 96: E1298-E1302, 2011)