Follicle-Stimulating Hormone (FSH), Serum

Test ID:

704219

CPT code:

83001

Synonyms:

Pituitary Gonadotropin

Clinical Use:

Excessive FSH and LH are found in hypogonadism, anorchia, gonadal failure, complete testicular feminization syndrome, menopause, Klinefelter syndrome, alcoholism, and castration. FSH and LH are pituitary products, useful to distinguish primary gonadal failure from secondary (hypothalamic/pituitary) causes of gonadal failure, menstrual disturbances, and amenorrhea. Useful in defining menstrual cycle phases in infertility evaluation of women and testicular dysfunction in men. FSH is commonly used with LH, which also is a gonadotropin. Both are low in pituitary or hypothalamic failure. FSH and LH levels are high following menopause.

Test Information:

FSH is a glycoprotein consisting of two subunits (α- and β-chains). Its molecular weight is approximately 32,000 daltons. FSH together with LH (luteinizing hormone), belongs to the gonadotropin family. FSH and LH regulate and stimulate the growth and function of the gonads (ovaries and testes) synergistically.
FSH and LH are released in pulses from the gonadotropic cells of the anterior pituitary. The levels of the circulating hormones are controlled by steroid hormones via negative feedback to the hypothalamus. In the ovaries, FSH, together with LH, stimulates the growth and maturation of the follicle and hence also the biosynthesis of estrogens in the follicles.
In women, the gonadotropins act within the hypothalamus-pituitary-ovary regulating circuit to control the menstrual cycle. The FSH level shows a peak at midcycle, although this is less marked than with LH. Due to changes in ovarian function and reduced estrogen secretion, high FSH concentrations occur during menopause. The determination of FSH in conjunction with LH is utilized for the following indications: congenital diseases with chromosome aberrations, polycystic ovaries (PCO), amenorrhea (causes), and menopausal syndrome.
In men, FSH serves to induce spermatogonium development. Determination of the FSH concentration is used in the elucidation of dysfunctions within the hypothalamus-pituitary-gonads system. Depressed gonadotropin levels in men occur in azoospermia.