title: Amniotic fluid concentrations of dimeric inhibins, activin A and follistatin in pregnancy.
abstract: OBJECTIVE
  The feto-placental unit is the major source of circulating concentrations of inhibin A and activin A in human pregnancy. The aim of this study was to measure the amniotic fluid concentrations of inhibin A, inhibin B, activin A and follistatin in pregnancies bearing male and female fetuses.
  
  
  METHODS
  Amniotic fluid samples collected by amniocentesis were stored at -20 degrees C. Dimeric inhibins, 'total' activin A and 'total' follistatin were measured using specific two-site enzyme immunoassays. Samples were assayed blindly and the information on fetal sex was obtained from the cytogenetics laboratory.
  
  
  RESULTS
  Data show that amniotic fluid concentrations of inhibin A, inhibin B and activin A gradually increase with gestation whilst concentrations of follistatin are similar between weeks 15 and 20 of pregnancy. Mean amniotic fluid levels of inhibin A and inhibin B at 16 and 17 weeks gestation and mean activin A levels at 15 and 16 weeks gestation are considerably lower in pregnancies with male (n=24) compared with female (n=28) fetuses. Levels of follistatin are not different in the male and female fetal pregnancies at any studied gestation.
  
  
  CONCLUSIONS
  The results indicate that amniotic fluid contains high concentrations of inhibins (A and B), activin A and follistatin in early pregnancy suggesting that these hormones are produced by the fetal membranes and may be involved in the development of the fetus.
authors.affiliation: Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
authors.forename: S
authors.initials: S
authors.lastname: Muttukrishna
authors.forename: P
authors.initials: P
authors.lastname: Chamberlain
authors.forename: L W
authors.initials: LW
authors.lastname: Evans
authors.forename: J
authors.initials: J
authors.lastname: Asselin
authors.forename: N P
authors.initials: NP
authors.lastname: Groome
authors.forename: W L
authors.initials: WL
authors.lastname: Ledger
mesh_terms: D028341:Activins; D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism*; D005260:Female; D038681:Follistatin; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007265:Inhibins / Q000378:metabolism*; D008297:Male; D011247:Pregnancy
chemical_list: D038681:Follistatin; D006023:Glycoproteins; D028341:Activins; D007265:Inhibins