Anti-Müllerian hormone

Anti-Müllerian hormone (AMH) is a dimeric glycoprotein that inhibits the development of the Müllerian ducts in a male embryo. It is named after Johannes Peter Müller. It has also been called Müllerian inhibiting factor (MIF), Mullerian inhibiting hormone (MIH), and Mullerian inhibiting substance (MIS).

Structure
AMH is a protein hormone structurally related to inhibin and activin, and a member of the transforming growth factor-β (TGF-β) family. It is present in fish, reptiles, birds, marsupials, and placental mammals.

Gene
In humans the gene for AMH is AMH, on chromosome 19p13.3, while the gene AMH-RII codes for its receptor on chromosome 12.

Embryogenesis
In mammals AMH is secreted by Sertoli cells of the testes during embryogenesis of the fetal male and prevents the development of the mullerian ducts into the uterus and other mullerian structures. The effect is ipsilateral, that is each testis suppresses Müllerian development only on its own side. In humans this action takes place by 8 weeks gestation. In female embryogenesis the absence of AMH allows for the development of upper vagina, uterus and cervix, and oviducts. Amounts of AMH that are measurable in the blood vary by age and sex. AMH works by interacting with specific receptors on the surfaces of the cells of target tissues. The best known and most specific effect, mediated through the AMH type II receptors, includes programmed cell death (apoptosis) of the target tissue (the fetal mullerian ducts).

Ovarian function
While AMH is measurable in males during childhood and adulthood, AMH cannot be detected in women until puberty. AMH is expressed by granulosa cells of the ovary in the reproductive age and controls the formation of primary follicles by inhibiting excessive follicular recruitment by FSH. It therefore has a role in folliculogenesis, and some authorities suggest it is a measure of some aspects of ovarian function useful in assessing conditions such as polycystic ovary syndrome and premature ovarian failure.

Other functions
AMH production by the Sertoli cells of the testes remains high throughout childhood but declines to low levels during puberty and adult life. AMH measurements have become widely used in the last few years in the evaluation of testicular presence and function in infants with intersex conditions, ambiguous genitalia, and cryptorchidism.

Pathology
In men, inadequate embryonal AMH activity can lead to the Persistent mullerian duct syndrome (PMDS), in which a rudimentary uterus is present and testes are usually undescended. The AMH gene (AMH) or the gene (AMH-RII) for its receptor are usually abnormal.

Research
AMH has been synthesized. Its ability to inhibit growth of tissue derived from the Müllerian ducts has raised hopes of usefulness in the treatment of a variety of medical conditions including endometriosis, adenomyosis and uterine cancer. Research is underway in several laboratories.