Anti-Müllerian hormone (AMH) is a dimeric glycoprotein that inhibits the development of the Müllerian ducts in a male embryo. 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 reptiles, birds, marsupials, and 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.

Embryogensis

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 testes suppresses Müllerian development on its side own only. 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).

Other Functions

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 inhibits oocyte meiosis. 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.

See also

Sexual differentiation