Prolactin is a hormone that affects many different hormones in the body. Present in both men and women, it rarely causes problems, but those who care about their health should understand what it is and how it impacts the body’s overall health and well-being. Prolactin, as its name implies, is a hormone that promotes lactation or breast milk production in mammals and is responsible for a number of other functions and systems. Prolactin is created in the front portion of the pituitary gland in your brain, as well as in the uterus, brain, breasts, prostate, adipose tissue, skin, and immune cells.
How is prolactin controlled?
One of the main regulators of the production of prolactin from the pituitary gland is the hormone called dopamine, which is produced by the hypothalamus, the part of the brain directly above the pituitary gland. Dopamine restrains prolactin production, so the more dopamine there is, the less prolactin is released. Prolactin itself enhances the secretion of dopamine, so this creates a negative feedback loop.
Estrogen is another key regulator of prolactin and has been shown to increase the production and secretion of prolactin from the pituitary gland. Many studies have shown small increases in prolactin in the blood circulation of women during stages of their reproductive cycle where estrogen levels are at their highest. This is also the case during and after pregnancy, which makes sense, since a higher level of circulating prolactin is needed to cause lactation to start.
In addition to dopamine and oestrogen, a whole range of other hormones can both increase and decrease the amount of prolactin released in the body, with some examples being thyrotropin-releasing hormone, oxytocin and anti-diuretic hormone.
Why is the prolactin test done?
Women with prolactinoma symptoms may need the test. Prolactinoma is a noncancerous tumor on the pituitary gland that produces high levels of prolactin. Symptoms of prolactinoma in women include:
- unexplained headaches
- visual impairment
- galactorrhea, or lactation outside of childbirth or nursing
- pain or discomfort during sex
- abnormal acne
The test is usually performed on people with prolactinoma to keep track of the tumor’s response to treatment. In addition, the prolactin test may be needed if you’re having fertility problems or irregular periods. The test can also rule out other pituitary gland or hypothalamus problems.
What does Prolactin do?
Prolactin is released when a newborn baby suckles at his/her mother's breast, causing the production of milk. However, this is just the primary and most well-known purpose of prolactin. Prolactin function is still being studied, but research seems to show a variety of purposes for this hormone. For instance, it also regulates behavior, the immune system, metabolism, reproductive systems, and many other bodily fluids. This makes it a crucial hormone for overall health and well-being, for both men and women. Production of prolactin is controlled by two main hormones: dopamine and estrogen. These hormones send a message to the pituitary gland primarily indicating whether to begin or cease the production of prolactin. Dopamine restrains the production of prolactin, while estrogen increases it.
Treatment for high prolactin levels
Dopamine agonists such as bromocriptine are the most common treatment for high levels of prolactin. These medications help the brain produce dopamine to control high prolactin levels. They can also shrink prolactinoma tumors. Your doctor may recommend that you take cabergoline. Cabergoline is a newer prolactinoma treatment with milder side effects than other common prolactinoma medications. Talk to your doctor about cabergoline if you face severe side effects from other treatments, including bromocriptine.
Prolactinoma and hyperprolactinemia are not life-threatening. The worst side effects of medications usually go away after treatment. Infertility caused by high prolactin levels can be reversed once prolactin levels return to normal. Your quality of life will remain high even if you need long-term treatment.