Liu HL, et al. - Since a large proportion of patients with the polycystic ovarian syndrome (PCOS), one of the most common female endocrine disorders affecting about 5–10% women of reproductive age, present obesity and insulin resistance, researchers studied the role of peroxiredoxin (PRX)3 [predominantly located in mitochondria and plays an important role of free radical scavenging] in the pathogenesis of PCOS featured in insulin resistance. To identify plasma PRX3 in PCOS patients and control subjects, the enzyme-linked immunosorbent assay was performed. No significant difference was found between PCOS patients and controls in fasting plasma PRX3. There was no association between fasting plasma PRX3 and fasting plasma glucose or insulin. PCOS patients exhibited higher levels of both glucose and insulin vs controls after the oral glucose tolerance test (OGTT). Investigators found that the PRX3 plasma level increased significantly at 2 hours and began falling back at 3 hours of OGTT. Under baseline conditions, PRX3 does not show its antioxidant function. Instead, in patients with PCOS, PRX3 responds to oxidative stress caused by a rapid increase in insulin and glucose.