title: Effect of pituitary desensitization on the early growing follicular cohort estimated using anti-Mullerian hormone.
abstract: BACKGROUND
  This study evaluated the effect of pituitary desensitization on the early growing follicle population through assessment of serum anti-Mullerian hormone (AMH) concentration. Other markers of ovarian reserve, basal follicular stimulating hormone (FSH), luteinizing hormone (LH), estradiol, inhibin-B and three-dimensional ultrasound ovarian parameters were also assessed for comparison.
  
  
  METHODS
  One hundred and two subjects aged <40 years with FSH levels <12 IU/l underwent venepuncture and transvaginal ultrasound in the early follicular phase of the menstrual cycle and after 14 days of down-regulation using gonadotrophin releasing hormone (GnRH) agonists. Serum levels of AMH and other markers of ovarian reserve measured during the early follicular phase were compared with those measured following down-regulation.
  
  
  RESULTS
  While AMH levels increased significantly by approximately 32% (P < 0.01), there was a significant decline of approximately 40-50% (P < 0.01) in the levels of inhibin-B, FSH, LH and estradiol. Down-regulation treatment was also associated with a decrease (P < 0.01) in mean ovarian volume and in ovarian blood flow, but no difference was seen in the antral follicle count.
  
  
  CONCLUSIONS
  Pituitary desensitization results in a significant increase in AMH levels, which implies that either the secretion of AMH by early growing follicles is enhanced or that the size of this follicle cohort is increased. The number of antral follicles visualized on ultrasound in the early follicular phase and at down-regulation appears unchanged, suggesting that any effect is restricted to the smaller selectable follicles. Our results may explain the enhanced ovarian response to conventional controlled ovarian stimulation and higher pregnancy rates when pretreatment with GnRH-agonists is employed.
authors.affiliation: Academic Division of Reproductive Medicine and Surgery, School of Human Development, Queen's Medical Centre, University of Nottingham, Nottingham, Nottinghamshire, UK. k.jayaprakasan@nottingham.ac.uk
authors.forename: K
authors.initials: K
authors.lastname: Jayaprakasan
authors.forename: B K
authors.initials: BK
authors.lastname: Campbell
authors.forename: J F
authors.initials: JF
authors.lastname: Hopkisson
authors.forename: J S
authors.initials: JS
authors.lastname: Clewes
authors.forename: I R
authors.initials: IR
authors.lastname: Johnson
authors.forename: N J
authors.initials: NJ
authors.lastname: Raine-Fenning
mesh_terms: D000328:Adult; D054304:Anti-Mullerian Hormone / Q000378:metabolism*; D015331:Cohort Studies; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D006801:Humans; D007265:Inhibins / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D006080:Ovarian Follicle / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism*; D011446:Prospective Studies; D014463:Ultrasonography / Q000379:methods
chemical_list: C422364:inhibin B; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007265:Inhibins; D054304:Anti-Mullerian Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone