[Nattylocs]

Causes
Prolactinomas cause symptoms either due to the hormonal effects of excess PRL or due to the space-occupying effects and the pressure which they exert on the pituitary gland and the critical neurovascular structures that surround it such as the optic nerves. The hormonal symptoms resulting from hyperprolactinemia are different in males than in females.

Prolactinomas, are the most common cause of hyperprolactinemia, but there are several other causes of hyperprolactinemia that most importantly include the use of certain "anti-dopaminergic" medications (prolactin secretion from the pituitary gland is normally suppressed by the brain chemical, "dopamine"), these include Metoclopramide (Reglan), or anti-depressants such as Fluoxetine (Prozac), an underactive thyroid gland (hypothyroidism), and other types of pituitary tumors that arise in or near the pituitary gland- as those may compress the pituitary stalk and block the flow of dopamine from the brain to the prolactin-secreting cells causing hyperprolactinemia, this is commonly known as "stalk effect".