what is prolactin and its functions?

December 27, 2023by Dr. Shehrezad Czar0

Prolactin, a hormone produced by the pituitary gland, is primarily known for its role in lactation. However, its functions extend beyond this, influencing various aspects of reproductive health and bodily functions in both men and women. This article provides a comprehensive overview of this hormone, exploring its roles, regulatory mechanisms, and the implications of its imbalance.

Introduction to Prolactin

It is a peptide hormone secreted by the anterior pituitary gland. It is structurally similar to growth hormone and placental lactogen, playing a key role in reproductive health. While it is best known for its role in lactation, it also has other significant functions.

Primary Functions

Lactation: it stimulates breast milk production after childbirth. It works in concert with other hormones like estrogen and progesterone to prepare the breasts for lactation during pregnancy and maintain milk supply after birth.

Reproductive Health: In women, prolactin supports the regularity of menstrual cycles and maintains the corpus luteum, which is essential for fertility. In men, it has a role in testosterone production and sperm maturation.

Immunoregulatory Function: It has been found to have immunoregulatory functions. It influences the development of immune cells and the immune response.

Metabolic Regulation: Prolactin can impact metabolic processes, influencing fat metabolism and insulin sensitivity.

Osmoregulation: Although its role is less pronounced than other hormones, it can influence water and electrolyte balance in the body.

Regulation of Prolactin

Its secretion is primarily regulated by the hypothalamus:

Prolactin-Inhibiting Factors: Dopamine, produced by the hypothalamus, is the primary inhibitor of prolactin secretion. It prevents hormone release in the absence of pregnancy or nursing.

Prolactin-Releasing Factors: Factors like estrogen and thyrotropin-releasing hormone can stimulate its release.

Feedback Mechanisms: The body’s feedback mechanisms regulate prolactin levels based on the need for lactation and other physiological factors.

Prolactin in Men

While it is more prominent in female physiology, it also plays important roles in men:

Fertility: It influences testosterone levels and sperm production, contributing to male fertility.

Sexual Health: It can affect sexual function, although its exact role is complex and not fully understood.

Prolactin Imbalance and Its Implications

Hyperprolactinemia: This condition is characterized by excessively high levels of prolactin, which can lead to various health issues. In women, it can cause irregular menstrual cycles, infertility, and galactorrhea (unintended breast milk production). In men, it may lead to reduced libido, impotence, and infertility.

Causes of Hyperprolactinemia: Common causes include pituitary tumors (prolactinomas), certain medications, thyroid dysfunction, and kidney disease.

Hypoprolactinemia: Low levels of this hormone are less common but can be associated with pituitary disorders.

Diagnosing Imbalance

Diagnosis involves blood tests to measure prolactin levels, along with imaging studies like MRI to examine the pituitary gland, if necessary.

Treatment of Imbalance

Medications: Dopamine agonists are commonly used to treat hyperprolactinemia, reducing its production.

Surgery: In cases of prolactinomas, surgery may be required to remove the tumor.

Managing Underlying Conditions: Treating conditions contributing to imbalance is crucial for restoring hormonal balance.

Lifestyle and Prolactin Levels

Certain lifestyle factors can influence prolactin levels. Stress, for instance, can lead to temporary increases in it. Adequate sleep and stress management can help maintain hormonal balance.


Prolactin, though primarily associated with lactation, has a wide range of functions affecting reproductive health, metabolism, and immunity. Understanding its roles and the implications of its imbalance is crucial for addressing disorders related to this hormone. Effective management of prolactin levels, through medical treatment and lifestyle adjustments, is key to maintaining hormonal health and overall well-being.

Also Read: what is the role of growth hormone in aging and athletic performance?

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