Prolactin

Prolactin (PRL), also known as luteotropic hormone or luteotropin, is a protein that in humans is best known for its role in enabling mammals, usually females, to produce milk. It is secreted from the pituitary gland in response to eating, mating, estrogen treatment, ovulation and nursing. Prolactin is secreted in pulses in between these events. Prolactin plays an essential role in metabolism, regulation of the immune system and pancreatic development.

Structure

Prolactin is a single-chain protein hormone, closely related to growth hormone. It is a protein that is made up of about 200 amino acids. The molecular weight of prolactin is approximately 23,000 Daltons.

Function

Prolactin has many effects on the body. The most important of these is the stimulation of the mammary glands to produce milk (lactation). It has a wide variety of effects including regulation of the immune system, brain functions, behavior, reproduction, water and salt balance, growth and development, and metabolism.

Clinical significance

High levels of prolactin in the blood (hyperprolactinemia) can cause various symptoms depending on the age and sex of the person. In women, high levels of prolactin can cause infertility, irregular menstruation, and milk production in women who are not pregnant or nursing. In men, high levels of prolactin can cause decreased libido, impotence, infertility, and enlargement of the breasts (gynecomastia).

See also

• Hyperprolactinemia
• Hypopituitarism
• Pituitary gland
• Pituitary adenoma

References

Prolactin Resources
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