Prolactin is responsible for milk production, reproductive function, metabolic function, body fluid regulation, immune system regulation, and behavioral function
Prolactin is a hormone responsible for milk production as well as a wide range of other functions, including reproductive function, metabolic function, body fluid regulation, immune system regulation, and behavioral function.
This makes it an important hormone for the overall health of both men and women.
Where is prolactin produced and how is it controlled?
Prolactin is mainly produced by lactotroph cells in the pituitary gland, where it is stored and released into the bloodstream. Prolactin is also produced in the uterus, immune cells, brain, breasts, prostate, skin, and adipose tissue.
Dopamine and estrogen are hormones that control prolactin production. These hormones convey signals to the pituitary gland, telling it to start or stop production:
- Dopamine inhibits prolactin production
- Estrogen increases prolactin production
Along with dopamine and estrogen, various other hormones can alter how much prolactin is released in the body—for example, thyrotropin-releasing hormone, oxytocin, and antidiuretic hormone.
What are the normal levels of prolactin hormone?
Prolactin tests measure the level of prolactin in the blood. Normal ranges for prolactin levels in the blood are as follows:
Prolactin levels can be affected by prolactin-secreting tumors, medications, hormonal imbalances, and stress.
What happens when prolactin levels are too high?
High levels of prolactin in the blood is called hyperprolactinemia.
Causes of hyperprolactinemia include:
- Pregnancy
- Stress
- Medications that reduce dopamine activity in the body (including certain antacids and antiemetics)
- Underactive thyroid
- Benign pituitary tumors (known as prolactinomas)
Symptoms of hyperlactatemia include:
- Unwanted milk production of milk
- Irregular menstrual cycle
- Estrogen deficiency (in women)
- Testosterone deficiency (in men)
- Low libido
Some of these conditions can be treated with medications that mimic the activity of dopamine in the body.
What happens when prolactin levels are too low?
Low levels of prolactin in the blood is called hypoprolactinemia. This condition is extremely rare and may occur in individuals with pituitary failure. It is commonly seen in postpartum women who are unable to produce adequate milk.
Medications that can cause hypoprolactinemia include::
- Intropin (dopamine)
- Levodopa (for Parkinson's disease)
- Ergot alkaloid derivatives (for severe headache)
In most cases, low prolactin levels don't cause medical problems. although some research suggests that they may reduce immune responses to certain diseases.