Prolactin-releasing peptide

Prolactin-releasing peptide (PrRP) is a peptide hormone that plays a crucial role in the regulation of prolactin secretion within the anterior pituitary gland. It was first identified in the late 1990s through its ability to stimulate prolactin release in rats. PrRP is encoded by the PRLH gene in humans and is involved in a variety of physiological processes beyond prolactin release, including stress response, food intake, and cardiovascular regulation.

Structure and Gene

PrRP is derived from a preprohormone encoded by the PRLH (prolactin-releasing hormone) gene located on chromosome 10 in humans. The preprohormone is processed to generate two active forms of PrRP, PrRP-31 and PrRP-20, named after the number of amino acids they contain. These peptides exert their biological effects by binding to the G protein-coupled receptor, GPR10.

Function

The primary function of PrRP is to stimulate the secretion of prolactin from the anterior pituitary gland, a process that is crucial for lactation and has effects on reproductive functions. However, research has shown that PrRP's role extends beyond prolactin regulation. It is involved in the modulation of the stress response, influencing food intake, and contributing to cardiovascular homeostasis. PrRP has been observed to have an anorexigenic effect, reducing food intake when administered centrally.

Regulation

The secretion and action of PrRP are regulated by various factors, including stress, nutritional status, and hormonal signals. Stress, for example, can increase PrRP expression, suggesting a role in the body's adaptive response to stress. The interaction between PrRP and other hormones, such as gonadotropin-releasing hormone (GnRH) and somatostatin, further illustrates the complex regulatory network controlling prolactin secretion.

Clinical Significance

Alterations in PrRP levels have been associated with several pathological conditions. For instance, elevated PrRP levels have been observed in patients with heart failure, indicating a potential role in cardiovascular disease. Additionally, abnormalities in PrRP signaling have been implicated in eating disorders and obesity, highlighting its significance in energy balance and metabolism.

Understanding the mechanisms of PrRP action and its interactions with other physiological systems may provide insights into the development of therapeutic targets for treating disorders related to prolactin dysregulation, stress, metabolic diseases, and cardiovascular conditions.

See Also

• Prolactin
• Anterior pituitary gland
• G protein-coupled receptor
• Stress
• Eating disorders