Fig. 3

Regulation of testicular AMH production by FSH and testosterone in normal and pathological conditions. Basal AMH production is independent of gonadotropins or androgens; however, FSH stimulates and testosterone inhibits AMH expression. In the fetal period and during the first months of postnatal life (I), the hypothalamic-gonadotrope is active: FSH stimulates AMH production, whereas testosterone cannot inhibit it because Sertoli cells do not yet express the androgen receptor. During childhood, and in boys >14 years-old with constitutional delay of puberty (II), the hypothalamic-gonadotrope is “quiescent”, resulting in little or no effect on basal AMH production. In boys with normal or precocious puberty (III) with high intratesticular androgen concentrations (central precocious puberty, testotoxicosis, Leydig cell tumors), testosterone inhibition overrides FSH stimulation, resulting in a decrease in serum AMH. In patients with central hypogonadism (IV), only basal AMH production is observed, with no further stimulation or inhibition. In patients with disorders of sex development due to androgen synthesis defects (V) or androgen insensitivity (VI), the positive effect of FSH cannot be antagonized by testosterone, resulting in high AMH production in infancy and pubertal age. AR: androgen receptor; CAIS: complete androgen insensitivity syndrome; CDP: constitutional delay of puberty; FSH-R: FSH receptor; LH-R: LH receptor; T: testosterone