A patient is treated with a gonadotropin-releasing hormone (GnRH) infusion. An intravenous line is placed and connected to a reservoir through a computerized pump. The pump is programmed to deliver a predetermined dose of GnRH every 90 minutes, which results in a sharp rise in serum GnRH levels with each dose, followed by a rapid return to baseline. LH and FSH levels are monitored in the initial phase of treatment. Which of the following is the most likely indication for using this GnRH infusion?

Question

A patient is treated with a gonadotropin-releasing hormone (GnRH) infusion.  An intravenous line is placed and connected to a reservoir through a computerized pump.  The pump is programmed to deliver a predetermined dose of GnRH every 90 minutes, which results in a sharp rise in serum GnRH levels with each dose, followed by a rapid return to baseline.  LH and FSH levels are monitored in the initial phase of treatment.  Which of the following is the most likely indication for using this GnRH infusion?

Quizplus · Accepted Answer

11ec160b_3cb5_eed8_9249_4f490eb4f1b8_MD0001_00 Gonadotropin-releasing hormone (GnRH) is a polypeptide that is normally released from the anterior hypothalamus in a pulsatile manner. GnRH is carried to the anterior pituitary via the portal circulation, where it stimulates FSH and LH production. Pulsatile stimulation of pituitary gonadotrophin cells by GnRH leads to upregulation of GnRH receptors and enhanced FSH and LH secretion. FSH and LH are responsible for development of the dominant follicle in the ovaries. Optimal frequency and amplitude of GnRH pulses are crucial for FSH and LH release and subsequent ovulation. Anovulation due to hypogonadotropic hypogonadism is a common form of infertility that can be treated by pulsatile administration of GnRH. GnRH has a very short half-life and is given by a programmable pump that delivers a predetermined dose at physiologic intervals. Ovulation occurs in most patients in 10-20 days. Signs of ovulation include loss of a dominant follicle on ultrasound, surge in urine LH levels, rise in serum progesterone levels, and rise in basal body temperature. (Choices A, B, D, and E) Constant, rather than pulsatile, GnRH activity causes down-regulation of the GnRH receptors on pituitary gonadotrophin cells, which suppresses LH and FSH secretion. Although it is possible to use a pump to administer GnRH at a steady rate, it has a very short half-life, and long-acting GnRH analogs (eg, leuprolide) are easier to use and can be given monthly by intramuscular injection. Long-acting GnRH analog therapy is used when suppression of gonadal function is desired, such as in certain patients with prostate cancer, endometriosis, precocious puberty, or premenopausal breast cancer. Educational objective: Pulsatile administration of gonadotropin-releasing hormone (GnRH) stimulates FSH and LH release and is useful for the treatment of infertility. Nonpulsatile (constant) infusion of GnRH, or a long-acting analog, suppresses FSH and LH release and subsequently suppresses gonadal function. __________ References: Use of gonadotropin-releasing hormone agonists to trigger ovulation. (http://www.ncbi.nlm.nih.gov/pubmed/11939159)

A Patient Is Treated with a Gonadotropin-Releasing Hormone (GnRH) Infusion