Conference Coverage

Prolactin, the pituitary, and pregnancy: Where’s the balance?



– Management of fertility and reproduction for women with prolactin-secreting pituitary tumors is a balancing act, often in the absence of robust data to support clinical decision making. So judgment, communication, and paying attention to the patient become paramount considerations, said endocrinologist Mark Molitch, MD, speaking at the annual meeting of the Endocrine Society.

The first step: restoring fertility

“Remember that our patients that have hyperprolactinemia are generally infertile,” said Dr. Molitch, Martha Leland Sherwin Professor of Medicine at Northwestern University, Chicago. “You really need to restore prolactin levels to close to normal, or normal, to allow ovulation to occur,” he said.

Dr. Molitch noted that up to 94% of women with hyperprolactinemia will initially have anovulation, amenorrhea, and infertility, but restoration of normal prolactin levels usually corrects these.

“If you have a patient where you are unable to restore prolactin levels to normal, there are other methods” to consider. Patients may end up using clomiphene, gonadotropin-releasing hormone (GnRH) or gonadotropins, or even moving to in vitro fertilization in these cases, said Dr. Molitch.

Preferable to any of these, though, is achieving normal prolactin levels. “The critical thing is to think about what’s going on here, and then to try to lower the prolactin,” Dr. Molitch said.

In patients who are hyperprolactinemic, “the major action is occurring at the hypothalamic level,” with decreases in pulsatile secretion of GnRH, said Dr. Molitch. Next, there are resultant decreases in gonadotropin secretion, which in turn interrupt the ovary’s normal physiology. “There’s also an interruption in positive estrogen feedback in this cycle,” he said.

“So what’s new in this area is kisspeptin,” Dr. Molitch said, adding that the peptide activates the G-protein coupled receptor GPR54, found in the hypothalamus and pituitary. Infusion of kisspeptin stimulates secretion of luteinizing hormone, follicle stimulating hormone, and testosterone. Conversely, mutations that inactivate GPR43 result in hypogonadotropic hypogonadism, while activating mutations are associated with centrally caused precocious puberty (Biol Reprod. 2011 Oct;85[4]:650-60; Mol Cell Endocrinol. 2011 Oct 22;346[1-2]:29-3).


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