Neuroendocrine Effects of Hyperprolactinemia: Focus on Dopamine and Serotonin Systems

Hyperprolactinemia is characterized by unusually high levels of prolactin, a hormone primarily known for regulating reproductive functions. However, studies have shown that prolactin has also a significant impact on various neurotransmitter systems in the brain. This review examined the intricate relationship between hyperprolactinemia and neurotransmission, with a particular emphasis on the dopaminergic and serotonergic systems. Prolactin affects these systems in ways that can notably influence mood, behavior, and cognitive functions. One significant consequence of elevated prolactin is the disruption of dopaminergic signaling. Prolactin inhibits the release of dopamine and modifies the sensitivity of dopamine receptors, which may lead to the onset of neuropsychiatric disorders like depression, psychosis, and other mood-related issues. Moreover, high prolactin levels have been found to impact the serotonergic system, further worsening symptoms of depression, anxiety, and other mood disturbances. The review also evaluated the interactions between prolactin and other neurotransmitter systems, such as the GABAergic and glutamatergic systems, providing insights into the potential mechanisms through which hyperprolactinemia affects neuropsychiatric health. Additionally, the review discussed the complex relationship between prolactin and sex hormones, which not only affects reproductive health but also plays a role in regulating sexual behavior and mood. The clinical significance of hyperprolactinemia is considerable, as it is associated with various neuropsychiatric conditions. Current treatment options, including dopamine agonists, are explored as strategies to address the neurotransmitter imbalances linked to this condition. Furthermore, the review highlighted potential avenues for future research, including innovative therapeutic approaches that target neurotransmitter systems to tackle disorders related to hyperprolactinemia more effectively.