gonadotropiin

Gonadotropins are pituitary-derived hormones that stimulate the gonads (ovaries in females and testes in males). In humans the principal gonadotropins are follicle-stimulating hormone (FSH) and luteinizing hormone (LH). A related hormone, human chorionic gonadotropin (hCG), has LH-like activity and supports luteal function during pregnancy. Together they regulate gametogenesis and steroidogenesis.

Gonadotropins are heterodimeric glycoproteins composed of a common alpha subunit and a hormone-specific beta subunit, which determines receptor binding. They act on gonadal receptors, triggering intracellular signaling largely via the cAMP pathway. FSH primarily promotes growth and maturation of ovarian follicles and supports spermatogenesis in the seminiferous tubules; LH stimulates ovulation and corpus luteum formation in the ovary and stimulates testosterone production by Leydig cells in the testes.

In clinical practice, gonadotropins are used to treat infertility and to induce ovulation in assisted reproductive technology (ART) protocols. Recombinant or urinary-derived forms of FSH, sometimes in combination with LH activity (e.g., human menopausal gonadotropin, hMG), are employed, as is hCG to trigger final oocyte maturation. In men, gonadotropins may be used for hypogonadotropic hypogonadism or certain fertility treatments.

Endogenous gonadotropin release is controlled by GnRH from the hypothalamus and is subject to negative feedback from sex steroids and inhibin. The term derives from gonado- meaning the gonads and -tropin meaning to stimulate.