title: Follicular fluid levels of inhibin A, inhibin B, and activin A levels reflect changes in follicle size but are not independent markers of the oocyte's ability to fertilize.
abstract: OBJECTIVE
  To investigate the biochemical relationship between follicular/oocyte maturity and follicular inhibins and activin levels.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Research laboratory in university hospital.
  
  
  METHODS
  Thirty-five women undertook IVF/ICSI program.
  
  
  METHODS
  Individual follicular fluid aspirations, oocyte isolation, follicular fluid storage.
  
  
  METHODS
  Inhibin A, inhibin B, and activin A concentrations, oocyte retrieval, and fertility outcome.
  
  
  RESULTS
  Inhibin A, inhibin B, and activin A concentrations varied from 7.9 to 436 ng/mL, 9.7 to 786 ng/mL, and 1.7 to 267.9 ng/mL, respectively. There was no change of inhibin A concentrations, whereas inhibin B and activin A concentrations dropped dramatically as the follicles enlarged. Total follicular content of inhibin A and activin A increased, and inhibin B remained constant. Both inhibin A and inhibin B levels were significantly higher in those follicles from which an oocyte could be recovered, but they did not differ with respect to subsequent oocyte fertilization.
  
  
  CONCLUSIONS
  Inhibin A is actively produced throughout follicular growth to retain a set concentration. In contrast, inhibin B appears not to be actively produced, and the concentration drops as follicles enlarge. Activin A concentrations also decrease, but there is some extra synthesis. Higher levels of inhibin A and B are associated with oocyte presence but not with fertilization rates.
authors.affiliation: Institute of Social and Health Research, School of Health and Social Science, Middlesex University, Enfield, United Kingdom.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Wen
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Tozer
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Butler
authors.forename: Celia M
authors.initials: CM
authors.lastname: Bell
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Docherty
authors.forename: Ray K
authors.initials: RK
authors.lastname: Iles
mesh_terms: D028341:Activins / Q000032:analysis*; D000328:Adult; D015415:Biomarkers / Q000032:analysis; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D015571:Follicular Fluid / Q000737:chemistry*; D006801:Humans; D007246:Infertility / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D028322:Inhibin-beta Subunits / Q000032:analysis*; D007265:Inhibins / Q000032:analysis*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D006080:Ovarian Follicle / Q000166:cytology*; D011379:Prognosis; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D015415:Biomarkers; C422405:activin A; C422362:inhibin A; C422364:inhibin B; D028341:Activins; D007265:Inhibins; D028322:Inhibin-beta Subunits