Antimüllerian

Anti-Müllerian hormone (AMH), also called Müllerian-inhibiting substance, is a signaling protein of the transforming growth factor beta family. It is produced by different cells depending on sex and stage: in males, by Sertoli cells in the fetal testes; in females, by granulosa cells of preantral and small antral follicles within the ovaries. AMH acts by binding to the AMH receptor type II (AMHR2) and activating SMAD signaling.

In male development, AMH plays a key role in early embryogenesis by causing regression of the Müllerian ducts, thereby preventing the formation of female internal reproductive structures. In females, the precise physiological role of AMH is less clearly defined, but it is thought to regulate early follicle development by limiting the recruitment of primordial follicles and modulating follicle sensitivity to follicle-stimulating hormone (FSH).

Clinically, AMH is used as a biomarker of ovarian reserve. Serum AMH levels reflect the pool of recruitable follicles and generally decline with age. They are relatively higher in polycystic ovary syndrome (PCOS) and are used to predict ovarian response in assisted reproduction as well as to monitor gonadotoxic exposure from chemotherapy or radiotherapy. Elevated AMH can indicate granulosa cell tumors, where the tumor often secretes AMH.

Genetically, the AMH gene is located on chromosome 19, and its actions are mediated through AMHR2. AMH measurement is commonly performed via immunoassays, with reference ranges that vary by age and assay.

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