Prolactin-releasing hormone (PRH) is a peptide hormone that is responsible for stimulating the release of prolactin from the anterior pituitary gland. Prolactin is a hormone primarily known for its role in lactation, but it also plays important roles in reproductive behavior, immune regulation, and metabolism.
PRH is produced and secreted by the hypothalamus, which is a region of the brain that serves as a major control center for hormone production and release. When PRH is released into the bloodstream, it travels to the anterior pituitary gland and binds to specific receptors on the surface of cells called lactotrophs. This binding triggers a cascade of biochemical events within the cells, ultimately leading to the production and secretion of prolactin.
The release of PRH is tightly regulated by a variety of factors. For example, estrogen, which is a female sex hormone, stimulates the release of PRH, while dopamine, a neurotransmitter, inhibits its release. Additionally, stress and certain medications can affect the release of PRH.
Abnormal levels of PRH can have significant physiological consequences. Excess PRH secretion can lead to hyperprolactinemia, a condition characterized by high levels of prolactin in the blood. This can cause disruptions in menstruation, infertility, and lactation problems in women, and decreased libido and erectile dysfunction in men. Conversely, low levels of PRH can contribute to conditions such as hypoprolactinemia, which can result in infertility and inadequate milk production in breastfeeding women.
