What is the role of Anti-Mullerian Hormone (AMH) in the body?

Role of Anti-Müllerian Hormone (AMH) in the Body

Anti-Müllerian Hormone (AMH) is a glycoprotein produced by granulosa cells of pre-antral and small antral ovarian follicles that serves as a biomarker of ovarian follicular reserve and plays crucial roles in regulating follicular development by inhibiting primordial follicle recruitment and suppressing FSH action on developing follicles. 1

Biological Functions of AMH

AMH has several important physiological roles:

1. In male embryonic development:

   • Causes regression of Müllerian ducts in male embryos, preventing the development of female reproductive organs 2, 3
   • Produced by Sertoli cells in testes until puberty, then decreases to residual levels 2

2. In female reproductive function:

   • Acts as a "follicular gatekeeper" by:
     • Inhibiting recruitment of primordial follicles from the resting oocyte pool 1, 4
     • Suppressing FSH action on developing follicles 1, 4
     • Limiting follicle growth initiation and subsequent estradiol production 1

AMH Production Patterns Across Lifespan

• Males:

  • Significantly produced in Sertoli cells until puberty
  • Gradually decreases to residual values in adulthood 2

• Females:

  • Almost undetectable during infancy
  • Increases with onset of puberty as primordial follicles begin recruitment
  • Produced by growing follicles until they reach the dominant follicle stage
  • Gradually decreases throughout reproductive life as ovarian reserve diminishes
  • Falls below detectable levels in menopause 2

Clinical Applications of AMH

1. Assessment of ovarian reserve:

   • Serves as an ideal tool for evaluating follicular reserve 2
   • Advantage: serum levels don't fluctuate significantly during menstrual cycle 2
   • Correlates strongly with antral follicle count (AFC) 2

2. Diagnostic marker in specific conditions:

   • Elevated in Polycystic Ovary Syndrome (PCOS) 1
   • Marker for presence of testes in cryptorchidic males 2
   • Potential marker for granulosa cell tumors 5

3. Fertility assessment:

   • Predictor of ovarian response in assisted reproductive techniques 2, 5
   • Helps predict menopausal transition 5

Limitations and Challenges

• Lack of international standardization between different AMH assays 1
• Technical issues with sample handling, transport, and storage affect measurements 1
• Age-specific reference ranges are needed due to significant variability across lifespan 6, 1
• Not appropriate for PCOS diagnosis in adolescents due to naturally higher levels 6

Molecular Characteristics

• Member of the transforming growth factor beta (TGFβ) superfamily 1, 2
• Signals through two serine/threonine kinase receptors:
  • Type II receptor (AMHR2) is specific to AMH
  • Type I receptors are shared with bone morphogenetic proteins 7, 3
• Regulated by factors including SF1, SOX9, and FSH (positive regulators)
• Testosterone acts as a powerful downregulator 7

Clinical Considerations

• When interpreting AMH levels, age-specific reference ranges must be considered 6, 1
• AMH should not be used for PCOS diagnosis in adolescents or within 8 years post-menarche due to naturally higher levels that overlap with PCOS 6
• Different assays produce different numerical results, making standardization essential 1