Special Precautions/Comments:

Additional Information:

Prolactin is a hormone secreted by lactotroph cells in the anterior pituitary which stimulates breast development in women and lactogenesis in nursing mothers. Serum levels are therefore increased in pregnancy and lactation. Prolactin secretion is pulsatile and negatively regulated by dopamine. 

Hyperprolactinaemia can cause amenorrhoea and infertility and therefore prolactin measurement is useful in the investigation of these. However, increased levels can be seen in women on oral contraceptives. Prolactin measurement is also used in the investigation of gynaecomastia (breast development) in men. Increased prolactin can also be seen in stress, particularly in needle-phobic patients, and a cannulated prolactin measurement can overcome this.  

Prolactin may also be measured to investigate pituitary function and significant hyperprolactinaemia is suggestive of a prolactin-secreting pituitary adenoma (known as a prolactinoma). The level of prolactin can help differentiate between a micro or macroadenoma. In contrast, low levels of prolactin may be seen in hypopituitarism, where there is no production of 1 or more of the pituitary hormones. 

Macroprolactin are biologically inactive IgG complexes which can cause interference in the prolactin assay leading to a falsely elevated result. Macroprolactin is screened for in the laboratory to exclude interference in elevated results.