Regulation of ovarian function: structural characterization and role of anti-Müllerian hormone (AMH).
Year: 2013
Type: article
Abstract: "Background: The anti-müllerian hormone (AMH) is a member of the transforming growth factor β (TGF-β) superfamily, which exerts important functions on local regulation of folliculogenesis. Although in vivo and in vitro studies suggest that AMH affects the primordial follicle assembly and activation, as well as the responsiveness of growing follicles to folliclestimulating hormone (FSH), the physiological mechanisms involved in these actions remain to be fully elucidated. Given the relevance of AMH in the folliculogenesis, this review aimed to describe the structural features, expression and the main biological effects of AMH on the follicular development. Review: Originally identifi ed as a testicular product, AMH is responsible for regression of the Mü llerian ducts during sexual differentiation of male embryos. In females, AMH is produced almost exclusively by granulosa cells of ovarian growing follicles, whose serum levels are positively related to the number of ovarian follicles, making AMH an excellent clinic marker of ovarian reserve. Along this work, it was shown aspects related to the structural characterization of AMH and its specifi c type II receptor (AMHRII). AMH is a glycoprotein dimer linked by disulfi de bonds. The mature protein comprises two unequal domains: a long N-terminal domain (110-kDa) and a short C-terminal domain (25-kDa), responsible for the biological activity of the molecule. The AMHRII is an 82-kDa protein. Like others members of TGF-β family, AMH signals through two types of serine/threonine kinase receptors called type I and type II, and two types of Smad proteins, receptor-regulated Smad (R-Smad) and common Smad, Smad4. However, the identity of the AMH type I receptor is not clear; three type I receptors of Bone Morphogenetic Proteins (BMPs), Alk2, Alk3 and Alk6 may transduce AMH signals. AMH expression was detected in granulosa cells of growing follicles and it decreases once FSH-dependent follicular growth has been initiated. Follicles showing signs of atresia also have decreased or no AMH expression, and expression is completely lost in corpora lutea. AMH is not found in primordial follicles, theca cells, oocytes or the interstitium. This specifi c expression pattern of AMH suggests a role in the two regulatory steps of folliculogenesis: the recruitment of primordial follicles and the sensitivity of large preantral and small antral follicles to FSH. Evidences obtained from studies with AMH-knockout mice suggest that AMH inhibits activation of primordial follicles into the growing pool, while at cyclic recruitment AMH lowers the FSH-sensitivity of follicles. In addition, AMH was recently implicated in the primordial follicle assembly. AMH was found to inhibit primordial follicle assembly and decrease the initial primordial follicle pool size in a rat ovarian organ culture. Conclusion: From this review, we can conclude that AMH plays a key role on the modulation of ovarian function in mammals. This substance is an"
Institutions: Universidade Estadual do Ceará, Universidade de São Paulo
Language: English
Subfield: Reproductive Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W800603834