title: Circulating inhibins and activin A during GnRH-analogue down-regulation and ovarian hyperstimulation with recombinant FSH for in-vitro fertilization-embryo transfer.
abstract: OBJECTIVE
  We have investigated serial changes in plasma concentrations of inhibin A, inhibin B, pro alpha C and activin A in women undergoing stimulation with recombinant FSH in 'long-protocol' down-regulated cycles of IVF treatment.
  
  
  METHODS
  Blood samples were collected during the entire IVF treatment cycle at points coinciding with the early follicular phase of the cycle preceding treatment, pituitary down-regulation, stimulation with recombinant FSH, ovulatory triggering, and the luteal phase of the cycle. In patients who achieved conception, blood samples were also taken during the first 2 weeks of pregnancy. All samples were analysed for inhibin A, inhibin B, pro alpha C, activin A and oestradiol.
  
  
  METHODS
  Fifteen women with normal ovarian function undergoing IVF treatment with tubal factor, mild endometriosis or idiopathic infertility.
  
  
  RESULTS
  During pituitary desensitization, both inhibin A and inhibin B were significantly (P < 0.001, P = 0.002, respectively) reduced whereas levels of pro alpha C and activin A were largely unaltered. Levels of both inhibins rose markedly (P < 0.01) during FSH stimulation and a further rise in inhibin A was detected on the day after ovulatory trigger. Levels of both inhibin A and inhibin B then fell during and after oocyte pickup and continued to fall during the luteal phase. Activin A levels rose less markedly during gonadotrophin stimulation. Statistical analysis showed a high degree of correlation between the number of follicles (> 10 mm) and serum inhibin A (r = 0.65, P < 0.01) and pro alpha C (r = 0.65, P < 0.01) concentrations during the late follicular phase.
  
  
  CONCLUSIONS
  These results indicate that ovarian production of dimeric inhibin A and B are gonadotrophin dependent, whereas activin A may have a significant gonadotrophin independent or extra-gonadal source. Inhibin A and pro alpha C may be useful markers for monitoring the effects of gonadotrophin stimulation.
authors.affiliation: Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford, UK.
authors.forename: G M
authors.initials: GM
authors.lastname: Lockwood
authors.forename: S
authors.initials: S
authors.lastname: Muttukrishna
authors.forename: N P
authors.initials: NP
authors.lastname: Groome
authors.forename: P G
authors.initials: PG
authors.lastname: Knight
authors.forename: W L
authors.initials: WL
authors.lastname: Ledger
mesh_terms: D028341:Activins; D000328:Adult; D002064:Buserelin / Q000008:administration & dosage; D015536:Down-Regulation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives; D006801:Humans; D007265:Inhibins / Q000097:blood*; D010053:Ovary / Q000187:drug effects*; D010455:Peptides / Q000097:blood*; D010902:Pituitary Gland / Q000187:drug effects; D029584:Prostatic Secretory Proteins; D011994:Recombinant Proteins / Q000008:administration & dosage; D013268:Stimulation, Chemical
chemical_list: D010455:Peptides; D029584:Prostatic Secretory Proteins; D011994:Recombinant Proteins; C043076:beta-microseminoprotein; C094377:inhibin-alpha subunit; D028341:Activins; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D005640:Follicle Stimulating Hormone; D002064:Buserelin