Follicle stimulating hormone (FSH) and luteinizing hormone (LH) are hormones produced by the pituitary gland that control the recruitment and development of ovarian follicles, each of which contains one egg. FSH and LH secretion are regulated by the brain (hypothalamus) by another hormone (neuropeptide) called gonadotropin releasing hormone (GnRH) that stimulates the pituitary to produce FSH and LH.
When a woman undergoes ovulation induction for an in vitro fertilization (IVF) cycle fertility specialists want to "control" the pituitary gland so that natural production of FSH and LH do not interfere with the cycle. During ovulation induction, FSH is given by injection until the follicles are mature and ready for retrieval. Once the follicles mature in a natural cycle, the hypothalamus signals the pituitary to release LH, which initiates ovulation. In an IVF cycle, this surge of LH must not occur before the eggs are retrieved or the cycle would be "lost.”
 Lupron is given during an IVF cycle stimulation to down-regulate or suppress the pituitary gland thereby preventing an LH surge from interfering with the cycle. FSH is given by injection and the growth and maturation of the follicles is closely monitored. Lupron also essentially blocks the production of estrogen, which is why it is effective in treating endometriosis. (Endometrial tissue is dependent upon estrogen for growth and support).
Once the fertility specialist judges that the follicles are mature, an injection of human chorionic gonadotropin (hCG) is given and egg retrieval is scheduled. Eggs will not be obtained at the time of egg retrieval unless hCG is given.
Ganirelix Acetate and Cetrotide produce the same effects as Lupron albeit by different mechanisms. These products are known as GnRH antagonists and they block the production of LH and FSH by the pituitary. Ganirelix Acetate/Cetrotide act more rapidly to block FSH/LH production compared to Lupron, therefore they can be given in lower doses for shorter periods of time.
Since all of these products produce a down-regulated state (natural production of reproductive hormones is blocked), they produce side effects similar to menopause if taken for an extended time. These side effects can include hot flashes, mood swings, nausea, and many others. See the manufacturers Web site for detailed information. |
