FSH is a glycoprotein secreted by the anterior pituitary. It is composed of two dissimilar subunits. The alpha chain is identical to that of LH, and very similar to TSH and HCG. The beta chain differs considerably from HCG, LH and TSH, and confers biological and immunological specificity.
LH and FSH are members of the gonadotropin family. They regulate and stimulate the growth and function of the gonads (ovaries and testes) synergistically.
In women, within a control system involving the hypothalamus, anterior pituitary and the ovaries, LH and FSH, are responsible for the cyclical ovarian changes during the menstrual cycle.
LH and FSH are released from the Gonadotrophic cells of the Anterior Pituitary into the blood stream. They act upon the ovaries to stimulate the growth and maturation of the follicle. The levels of circulating hormones are regulated by steroid hormones via negative feedback to the hypothalamus. There is a mid-cycle surge of FSH although this is not as marked as for LH.
At menopause, ovarian function ceases, leading to high levels of FSH due to the removal of the negative feedback mechanisms.
In males, FSH serves to induce spermatogonium development. Pituitary dysfunction can result in low levels of FSH and cause infertility. The functional state of the pituitary can be determined dynamically after the administration of LH-RH (LH-RH Stimulation test).
Determination of FSH is useful for investigating dysfunction of the Hypothalamus – Pituitary – Gonads system. e.g. Turner’s syndrome, polycystic ovaries, Amenorrhea, Menopausal syndrome and Primary Testicular Failure.
Children: 0.2 – 3.8 mIU/mL
Males: 1.6 – 11.0 mIU/mL
Follicular: 3.3 – 11.3 mIU/mL
Ovulatory: 5.2 – 20.4 mIU/mL
Luteal: 1.8 – 8.2 mIU/mL
Post-menopause: greater than 30 mIU/mL
- Three patient identifiers from
- N.H.S. number
- Unit Number