Mode of Action
GnRH antagonists competitively and reversibly bind to GnRH receptors in the pituitary gland, blocking the release of luteinising hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary. In men, the reduction in LH subsequently leads to rapid suppression of testosterone release from the testes; in women it leads to suppression of estrogen release from the ovaries.
Unlike the GnRH agonists, which cause an initial stimulation of the hypothalamic-pituitary-gonadal axis (HPGA), leading to a surge in testosterone or estrogen levels, GnRH antagonists have an immediate onset of action, rapidly reducing sex hormone levels without an initial surge.
Currently approved GnRH antagonists include the following:
- Cetrorelix
- Ganirelix
- Abarelix
- Degarelix
Read more about this topic: Gonadotropin-releasing Hormone Antagonist
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