Inhibin B

Clinical significance
Inhibin B is the most potent inhibitor of FSH and is produced by the ovarian follicles: it falls when their number is close to running out. The fall in inhibin B levels in turn leads to a rise in FSH.
In men, low inhibin B levels indicate poor or absent sperm production and have proved a good predictor of the success or failure of surgical sperm retrieval for subsequent
in vitro fertilisation.
In women, inhibin B can be used, like oestradiol, to monitor follicle growth (monitoring of superovulation cycles). Inhibin B also allows assessment of ovarian reserve and prediction of the response to ovulation induction.