Regulation of testicular anti-M ullerian hormone secretion.

Anti-Müllerian hormone (AMH) is a glycoprotein secreted by Sertoli cells from the time of testicular differentiation and is responsible for the regression of Müllerian ducts in the male fetus. The chronology of AMH expression is very important because Müllerian ducts lose their responsiveness a few days after AMH secretion begins, which suggests that the AMH gene is under precise transcriptional control. Steroidogenic factor 1 (SF-1) is the only transcriptional regulator with demonstrated action on AMH expression. Although necessary for AMH expression, SF-1 alone is not sufficient to induce AMH transcription. SRY expression is turned on in Sertoli cells just before AMH expression is initiated, but the effective implication of SRY in AMH regulation remains unclear. During puberty, AMH expression is regulated negatively by androgens and declines dramatically in seminiferous tubules with meiotic development. Low serum AMH levels are observed in both central and gonadotropin-independent precocious puberty, which suggests that gonadotropins do not down-regulate AMH at puberty. Serum AMH returns to normal infantile values 3-6 months after treatment. The absence of androgen response elements on the AMH promoter and the slow response to androgen withdrawal suggest that androgen regulation of AMH secretion is indirect. In patients with defects of androgen production or action, serum AMH reaches abnormally high levels in the neonatal and pubertal periods, which suggests a possible stimulatory role for gonadotropins that could be observed only in the absence of suppressive effects of androgens.