Anti-Müllerian Hormone: A Valuable Addition to the Toolbox of the Pediatric Endocrinologist

Figure 1

Regulation of testicular AMH secretion by gonadotropins and androgens. In general, the hypothalamus regulates LH and FSH secretion by the gonadotroph through the gonadotropin-releasing hormone (GnRH). LH acts on the LH receptor (LH-R) present in Leydig cells, inducing testosterone (T) secretion. FSH acts on the FSH receptor (FSH-R) present in Sertoli cells. The hypothalamic-pituitary-gonadal axis is active in the foetus and early infancy, is quiescent during childhood, and is reactivated at puberty. FSH is a moderate inducer of AMH secretion, whereas T, acting through the androgen receptor (AR), is a potent inhibitor of AMH production. In the normal foetus and infant, as well as in patients with the androgen insensitivity syndrome (AIS), the lack of AR expression results in high AMH production by Sertoli cells (I). During childhood, there is a physiologic hypogonadotropic state resulting in very low T; AMH levels remain high, but somewhat lower probably due to the lack of FSH stimulus (II). In normal or precocious puberty, T prevails over FSH, resulting in AMH inhibition (III). In congenital central hypogonadism, AMH is lower than in the normal boy because of the longstanding lack of FSH from foetal life; however, at pubertal age, the inhibitory effect of T is also absent, and AMH remains higher than in normal puberty (IV). In Leydig cell-specific primary hypogonadism (Leydig cell aplasia or hypoplasia due to LH-R defects or defects of steroidogenesis), the inhibitory effect of androgens is absent, and AMH levels are high. The orange area represents the testis. Thickness of lines is in correlation with hormone effect on its target. From [5], Copyright Karger AG, 2010, with permission.