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. Design and Method: Amniotic fluid samples collected by amniocentesis were stored at ¹20 ЊC. 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.

Modulation of Amniotic Fluid Activin‐A and Inhibin‐A in Women With Preterm Premature Rupture of the Membranes and Infection‐Induced Preterm Birth

“…18 Muttukrishana et al reported detectable levels of “total” activin-A from 15 to 20 weeks of gestation, but its concentration remained unchanged for the aforementioned GA interval. 25 A steady increase in the AF levels of inhibin-A from 15 to 18 weeks, was described by Wallace et al . 23,24 Petraglia and colleagues determined that between 23 to 40 weeks of gestation, activin-A was assayable in the AF of women with normal pregnancy outcomes.…”

“…15,22 However, most of our knowledge about human AF activin-A and inhibin-A is based on published reports which focused on their regulation in early pregnancy (8-20 weeks GA). 17,18,23,24,25,26,27 A common denominator for two of the referenced studies was that the levels of activin-A were higher in celomic fluid than in AF. 26,27 At 8-11 weeks, inhibin-A was undetectable in the AF.…”

Serum inhibin B in normal term-born male and female neonates during the first week of life

“…The causes of these acute changes in postnatal inhibin B concentration are unknown. Since we could not ®nd major changes in FSH levels, we speculate that in the postnatal period changes in paracrine growth factors, such as insulin and insulin-like growth factor-1, might potentiate FSH actions on granulosa cells and Sertoli cells inducing increased serum inhibin B concentrations in the 1st week of life [4,14,15,20]. The increase in inhibin B levels in neonates in the 1st week of life is in contrast with the changes in gonadal steroids: a brisk and short-lived increase in serum concentration of testosterone within hours of birth is seen in male neonates, while in both sexes the oestradiol concentration falls rapidly during the ®rst days of life [24,26].…”

“…The exact role of fetal inhibin B is unclear, but inhibins have been implicated in the regulation of steroid production in the fetal adrenal gland and gonads [25]. Although amniotic¯uid inhibin B concentrations have been shown to increase in the second trimester of pregnancy, it is not clear whether circulating concentrations of inhibin B are sucient to ful®l an endocrine role in suppression of FSH concentrations present in the third trimester [20]. We wondered whether measurement of serum inhibin B at the moment of neonatal screening on day 5 of life might give some information on gonadal development.…”

Upregulated INHBA Expression May Promote Cell Proliferation and Is Associated with Poor Survival in Lung Adenocarcinoma

“…Although the levels of specific growth factors are not available for most commercially obtained serums, multiple studies have demonstrated that the concentration of activin A rises during pregnancy in maternal serum and is detectable at high levels in amniotic fluid and fetal serum [37][38][39][40][41][42][43]. In addition, studies have shown that deletion of INHBA in mice results in severe craniofacial abnormalities, including cleft palate and lack of lower incisors.…”