Fig. 4

Schematic diagram of AMH and androgen in DOR and PCOS. In PCOS, elevated AMH stimulates LH expression by AMHR on hypothalamus and pituitary, increasing androgen secretion of theca cells. Meanwhile, elevated AMH inhibits FSHR expression and aromatase expression, which prevents the conversion of androgen to estrogen and follicle growth, leading to increase of androgen level. In return, elevated androgen stimulates AMH secretion of granulosa cells directly and indirectly. Therefore, elevated AMH and androgen promote mutually in a circle. In DOR, decreased AMH removes AMH induced inhibition of FSH expression, leading to faster conversion of androgen to estrogen and accelerated follicle consumption, which results in insufficient androgen and decreased ovarian reserve. In return, decreased androgen leads to decreased estradiol, elevated FSH, accelerated follicle consumption, and decreased AMH. AMH: anti-Müllerian hormone. DOR: diminished ovarian reserve. PCOS: polycystic ovarian syndrome. AMHR: receptor of AMH. FSH: follicle-stimulating hormone. LH: luteinizing hormone