From the Guidelines
Prolactin is a hormone that plays a crucial role in various bodily functions, including lactation, immune response, and reproductive function, with its primary function being to enable milk production in women after childbirth. The hormone prolactin is produced by the pituitary gland and has several important functions in the human body. Its main role is stimulating the mammary glands to produce breast milk during lactation, enabling women to nurse their children after childbirth. Beyond this reproductive function, prolactin helps regulate immune responses by influencing immune cell development and function 1. It also contributes to maintaining water and salt balance in the body and plays a role in metabolism. In men, prolactin helps regulate testosterone production and supports reproductive function. Prolactin levels naturally fluctuate throughout the day, typically being highest during sleep. Abnormal prolactin levels can cause health issues - elevated levels (hyperprolactinemia) may lead to irregular menstrual cycles, reduced fertility, decreased libido, and inappropriate milk production, while insufficient prolactin can prevent normal milk production in nursing mothers. The body carefully regulates prolactin through complex feedback mechanisms involving other hormones and neurotransmitters.
Key functions of prolactin include:
- Enabling milk production in women after childbirth
- Regulating immune responses
- Maintaining water and salt balance in the body
- Playing a role in metabolism
- Regulating testosterone production and supporting reproductive function in men According to recent guidelines, dopamine agonists, such as cabergoline, are effective in reducing prolactin levels and inducing tumor shrinkage in patients with prolactinoma 1. The use of cabergoline as a first-line therapy is recommended due to its superior effectiveness and lower adverse effect profile. Overall, prolactin is a vital hormone that plays a significant role in various bodily functions, and its regulation is crucial for maintaining overall health.
From the Research
Function of Prolactin
- Prolactin (PRL) is a hormone mainly secreted by lactotroph cells of the anterior pituitary gland, and it plays a crucial role in lactation during pregnancy 2, 3.
- In addition to its well-recognized role in lactation, prolactin is involved in other biological functions such as:
- Prolactin receptors are found in many tissues involved in metabolism and food intake, such as the pancreas, liver, hypothalamus, small intestine, and adipose tissue 4.
- The hormone has been implicated in multiple functions within the body, including driving adaptations of the maternal body to meet the physiological demands of pregnancy and lactation 4.
- Prolactin exists in three heterogenic forms, which possess varying biological activity, and the pattern of heterogeneity changes during pregnancy and lactation 3, 6.
Biological Actions of Prolactin
- Prolactin promotes milk production during lactation by stimulating the synthesis of milk proteins and lipids 3.
- It stabilizes and promotes transcription of casein mRNA, stimulates synthesis of alpha-lactalbumin, and increases lipoprotein lipase activity in the mammary gland 3.
- Prolactin may exert some of its biological effects by shifting the ratio of active to less active forms of the molecule 3.
- The hormone has been shown to control a variety of behaviors and play a role in homeostasis, and its secretion is regulated by various factors, including dopamine, light, audition, olfaction, and stress 6.