GnRH, also known as the Gonadotropin-releasing hormone and LHRH (Luteinizing-releasing hormone), plays a pivotal role throughout the course of a person’s life. Within the human body, there are several changes that occur when one transitions from childhood to adulthood. The catalysts responsible for these changes are hormones, which are produced when the walnut-sized pituitary gland sends chemical signals from the brain. There are many chemicals that are activated by this gland; one of which is GnRH.


GnRH functions as a chemical messenger that is sent from the brain to the genitals in a teenager. When GnRH is produced, it signals for the sexual organs to produce FSH (follicle stimulating hormone), and LH (luteinizing hormone).

FSH – The primary purpose of is to stimulate the maturation of reproductive organs. In women, the ovarian follicles are stimulated to release the eggs into the fallopian tubes on a regular basis (menstruation). In males, the testicles to start producing sperm, which needs testosterone to develop.

LH – This hormone supplies the reproductive organs with the base materials needed for FSH to work. In women, LH causes the process of ovulation, the act of the egg falling into the fallopian tube. In men, the corpus luteum stimulates the production of testosterone in the body, which helps the testicles produce more sperm regularly.

GnRH agonists

The purpose of a GnRH agonist is to elicit the biological reaction that occurs when GnRH is produced. Normally, the body’s agonist is the age of maturation. However, in some cases, synthetic agonists need to be used to stimulate the production of FSH, and LH. These include:

  • Teenagers who suffer from precocious puberty (premature puberty) take synthetic agonists because it actually slows the production of GnRH.
  • Those seeking sexual reassignment surgery take agonists to further stimulate female or male reproductive cycles.
  • Women seeking to have children can take agonists to stimulate their ovulation cycles in hopes of increasing their chance of conception.

GnRH Antagonists

The purpose of a synthetic GnRH antagonist is to suppress the body’s production of LH and FSH. Normally, antagonists are used after puberty is reached in order to prevent hyper-GnRH conditions. These uses include:

  • Treatment of hormone sensitive cancers such as breast or prostate cancer.
  • Reduce the levels of testosterone in aggressive men or estrogen in women (hyper-fertility).


To determine whether an antagonist or agonist needs to be used, a person can undergo a GnRH stimulation test, in which the patient fasts overnight and is then injected with GnRH to monitor the levels of FSH and LH in the body.

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