Fig. 1

Control of ovarian function via adrenal androgen production. *Under ovarian stimulation with gonadotropin very high; The figure depicts how androgen production in the zona reticularis of the adrenals can affect ovarian function: With low androgen production (for example insufficient capacity to sulfonize DHEA to DHEAS), growth and development of small growing follicles in ovaries (also called the functional ovarian reserve, FOR) is inhibited. LFOR develops, resulting in low estradiol and AMH levels due to declining granulosa cell mass. Due to decreasing feedback via estradiol, FSH production in the pituitary increases, leading to typically elevated FSH levels, usually attributed to a POI phenotype. These cases, however, actually represent a secondary form of ovarian insufficiency (SOI), primarily driven by adrenal hypoandrogenism. At the opposite extreme of ovarian function, androgen production by the adrenal cortex is responsible for some cases of PCOS