title: Elevated circulating levels of irisin and the effect of metformin treatment in women with polycystic ovary syndrome.
abstract: BACKGROUND
  Polycystic ovary syndrome (PCOS) is an insulin resistance (IR) state, like obesity and type 2 diabetes mellitus (T2DM). Although previous studies have suggested a correlation between irisin and the metabolic parameters associated with obesity and T2DM, the results have been inconsistent.
  
  
  OBJECTIVE
  Our objective was to (1) determine circulating irisin levels in women with PCOS and control subjects, (2) examine the relationship of irisin and conventional markers of insulin resistance, and (3) examine irisin changes with interventions modulating IR in PCOS women.
  
  
  METHODS
  This study was comprised of a series of cross-sectional and interventional studies of 178 PCOS and 123 healthy women from the general population and outpatients of the Internal Medicine Department at the Second Affiliated Hospital, Chongqing Medical University, China. Forty seven women with PCOS were randomly assigned to 6 months of oral metformin (850 mg bid). The oral glucose tolerance test (OGTT) and the euglycemic-hyperinsulinemic clamp (EHC) were performed to assess glucose tolerance and insulin sensitivity. Outcome measures were IR (AUC(Insulin) and M values) on an OGTT and EHC, irisin levels, and metabolic markers.
  
  
  RESULTS
  Circulating irisin was significantly higher in both overweight/obese (body mass index [BMI] ≥ 25 kg/m(2)) and PCOS women (P < .01). Circulating irisin levels correlated with BMI, WHR, FAT%, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), AUC(Insulin), homeostasis model assessment of insulin resistance (HOMA2-IR), M values, and free androgen index (FAI). During EHC, short-term hyperinsulinemia exhibited an inhibitory effect on irisin levels. After 6 months of metformin treatment, there was a significant decrease in circulating irisin in PCOS women following improved IR.
  
  
  CONCLUSIONS
  These data suggest that irisin may be a useful marker of IR in PCOS women.
authors: Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry (M.L., L.L.), College of Laboratory Medicine, Chongqing Medical University, 400010 Chongqing, China; Department of Endocrinology (M.Y., X.Z., X.F., W.H., W.Z., C.W., D.L., S.L., G.Y.), The Second Affiliated Hospital, Chongqing Medical University, 400010 Chongqing, China; and Department of Pediatrics (H.L.), University of Mississippi Medical Center, 2500 North State Street, Jackson, Mississippi 39216-4505.
authors: Minyan
authors: M
authors: Li
authors: Mengliu
authors: M
authors: Yang
authors: Xiaoxin
authors: X
authors: Zhou
authors: Xia
authors: X
authors: Fang
authors: Wenjing
authors: W
authors: Hu
authors: Wei
authors: W
authors: Zhu
authors: Cong
authors: C
authors: Wang
authors: Dongfang
authors: D
authors: Liu
authors: Shengbing
authors: S
authors: Li
authors: Hua
authors: H
authors: Liu
authors: Gangyi
authors: G
authors: Yang
authors: Ling
authors: L
authors: Li
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005353:Fibronectins / Q000097:blood*; D005951:Glucose Tolerance Test; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008077:Lipoproteins, LDL; D008687:Metformin / Q000627:therapeutic use*; D009765:Obesity / Q000097:blood / Q000150:complications / Q000188:drug therapy; D050177:Overweight / Q000097:blood / Q000150:complications / Q000188:drug therapy; D011085:Polycystic Ovary Syndrome / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D015854:Up-Regulation / Q000187:drug effects; D055815:Young Adult
chemical_list: C577593:FNDC5 protein, human; D005353:Fibronectins; D007004:Hypoglycemic Agents; D007328:Insulin; D008077:Lipoproteins, LDL; D008687:Metformin