title: Estradiol-to-testosterone ratio is associated with response to metformin treatment in women with clomiphene citrate-resistant polycystic ovary syndrome (PCOS).
abstract: BACKGROUND
  To investigate intrinsic alterations in ovarian steroidogenesis in women with clomiphene citrate (CC)-resistant polycystic ovary syndrome (PCOS) who ovulated after metformin treatment.
  
  
  METHODS
  Fifty-six women of reproductive age (18-40 years) diagnosed with CC-resistant PCOS received metformin for 12 weeks. If ovulation was successfully induced by CC after metformin treatment, the women were classified as responders. Circulating levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), testosterone (T), free testosterone (freeT), fasting insulin and sex hormone-binding globulin (SHBG) were determined at weeks 0, 4 and 12 of metformin treatment.
  
  
  RESULTS
  Thirty-seven women with CC-resistant PCOS finished the treatment course. There were no significant differences in circulating levels of FSH, E2, T, freeT and fasting insulin at weeks 0, 4, and 12 between responders and nonresponders. At week 4, responders showed significantly higher LH levels and higher LH/FSH ratios than non-responders (p < 0.005 and p < 0.05, respectively). After the 12-week treatment, responders demonstrated higher serum E2/T ratios and lower freeT levels than non-responders (p < 0.05 and p < 0.05, respectively).
  
  
  CONCLUSIONS
  The results suggest that in women with CC-resistant PCOS, elevated E2/T is associated with a better response to metformin.
authors.affiliation: Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Shang-Gwo
authors.initials: SG
authors.lastname: Horng
authors.forename: Tzu-Hao
authors.initials: TH
authors.lastname: Wang
authors.forename: Hsin-Shih
authors.initials: HS
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D002996:Clomiphene / Q000627:therapeutic use; D004351:Drug Resistance; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D008687:Metformin / Q000627:therapeutic use*; D011085:Polycystic Ovary Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D011863:Radioimmunoassay; D013739:Testosterone / Q000097:blood*
chemical_list: D002996:Clomiphene; D013739:Testosterone; D004958:Estradiol; D008687:Metformin