The Follicle Stimulating Hormone (FSH) is a hormone that is produced by the pituitary gland, a pea-sized gland in the brain. FSH plays an important role in the sexual development and reproductive function in men and women. It leads to sperm production in men, and in women it stimulates the ovaries to produce estrogen, and leads to the maturation of ovarian follicles.
FSH works in connection with the Luteinizing Hormone (LH) to ensure normal function of the ovaries. When the level of FSH peaks at the same time as an LH surge occurs, it causes ovulation to happen. In PCOS, there are rapid pulses of a hormone called GnRH, causing an increased LH:FSH ratio. This leads to the production of excess androgen and too little conversion of estradiol, which are connected to many of the symptoms of PCOS.
- Hormone Health Network (The Endocrine Society). Pituitary Gland. https://www.hormone.org/your-health-and-hormones/glands-and-hormones-a-to-z/glands/pituitary-gland (accessed 3. August 2020)
- Orlowski M. et al. Physiology, Follicle Stimulating Hormone. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK535442/ (accessed 3. August 2020)