Gonadotropin-Releasing Hormone Agonists (GnRH Agonist)

Definition - What does Gonadotropin-Releasing Hormone Agonists (GnRH Agonist) mean?

Gonadotropin-releasing hormone agonist (GnRH agonist, GnRH-A) is a synthetic hormone, most commonly used in assisted reproductive treatments (ART) to create an ovulation cycle that is medically controlled instead of biologically controlled. This is particularly valuable for in vitro fertilization (IVF), when GnRH agonist is used to spur the development of multiple eggs in one cycle. However, GnRH is also used for the medical treatment of several reproductive health conditions.

GnRH agonist should not be confused with GnRH antagonist, another synthetic hormone that produces similar results but on a different timeframe.

It is also known by the brand name Ganirelix.

FertilitySmarts explains Gonadotropin-Releasing Hormone Agonists (GnRH Agonist)

GnRH agonist was developed to mimic the biologically occurring gonadotropin-releasing hormone (GnRH). In the body, GnRH is responsible for triggering the ovulation process by prompting the release of two additional hormones: follicle stimulating hormone (FSH) and luteinizing hormone (LH).

Similar to GnRH, GnRH agonist causes a massive surge in the body’s output of FSH and LH. However, the body is unable to naturally sustain the continued release of these hormones. Therefore, ovulation stops. Once natural ovulation has ended, an ovulation induction (OI) medication is administered. Ovulation resumes, but to a heightened degree. As a result, there is rapid development of multiple eggs and follicles in the ovaries. When the eggs are harvested in preparation for the fertility treatment, multiple medically developed eggs are available, as opposed to the naturally occurring single egg. For a women preparing to undergo IVF, this is an advantageous technique, as the odds of a successful procedure increase with a higher number of viable eggs.

GnRH agonists are also being used as medical treatment, or tested for their potential in treating, a variety of female based reproductive diseases, including:

  • Endometriosis
  • Polycystic ovarian disease
  • Uterine fibroids
  • Irritable bowel syndrome
  • Certain cancers

Additionally, the use of GnRH agonist is being tested as a route to preserve fertility for cancer patients within the oncofertility field.

Common GnRH agonist medications include:

  • Lupron
  • Synarel
  • Zoladex
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