title: Variation in circulating antimüllerian hormone precursor during the periovulatory and acute postovulatory phases of the human ovarian cycle.
abstract: OBJECTIVE
  To determine whether the relative quantity of circulating AMH precursor (proAMH) declines relative to levels of the active form (AMHN,C) in the periovulatory phase of the ovarian cycle.
  
  
  METHODS
  Longitudinal study.
  
  
  METHODS
  Local community.
  
  
  METHODS
  Sixteen women aged between 18 to 30 years with regular menstrual cycles between 25 to 35 days long.
  
  
  METHODS
  None.
  
  
  METHODS
  Serum concentrations of proAMH and total AMH (proAMH and AMHN,Ccombined) measured by immunoassay, with relative levels of proAMH expressed as the AMH prohormone index (API = [ProAMH]/[Total AMH] × 100).
  
  
  RESULTS
  The mean API in the 11 eligible women fell from 20.7 during the luteinizing hormone (LH) surge period to 18.7 during the acute postsurge period. No statistically significant differences in the API were observed among samples taken at single time points in the early follicular, midfollicular, midluteal, and late luteal phases.
  
  
  CONCLUSIONS
  This study suggests that activation of AMH by proteolytic enzymes is largely stable throughout the ovarian cycle. However, there is a subtle but robust decrease in the level of proAMH relative to AMHN,Cin the acute postovulatory period. This may indicate that periovulatory increases in prohormone convertases cause increases in proAMH cleavage rates. Alternatively, rapid changes in the hierarchy of follicle developmental stages during ovulation may result in changes in the relative ratios of proAMH and AMHN,C.
authors.affiliation: Department of Anatomy, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand. Electronic address: michael.pankhurst@otago.ac.nz.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Pankhurst
authors.affiliation: Department of Anatomy, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand; Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: Yih Harng
authors.initials: YH
authors.lastname: Chong
mesh_terms: D000293:Adolescent; D000328:Adult; D054304:Anti-Mullerian Hormone / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D005260:Female; D005498:Follicular Phase / Q000097:blood*; D006801:Humans; D008137:Longitudinal Studies; D008183:Luteal Phase / Q000097:blood*; D010060:Ovulation; D011498:Protein Precursors / Q000097:blood; D059748:Proteolysis; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D011498:Protein Precursors; D054304:Anti-Mullerian Hormone
keywords: Menstrual cycle; ovarian cycle; prohormone convertases; total AMH