Ghrelin: A Multifaceted Peptide Beyond Just Growth Hormone Regulation
Background
Ghrelin, a 28-amino acid acylated peptide primarily produced by the stomach, is well-known for its potent growth hormone (GH)-releasing activity. This action occurs via specific hypothalamus-pituitary GH secretagogue (GHS) receptors. While its role in GH regulation is established, this review synthesizes evidence for ghrelin's broader endocrine and non-endocrine actions, highlighting its diverse physiological impact beyond just GH secretion.
Results
The review confirms ghrelin's primary role in stimulating GH release through hypothalamus-pituitary GHS receptors. However, it extensively details ghrelin's significant "non-endocrine" actions, including the stimulation of lactotroph and corticotroph secretion. Furthermore, ghrelin profoundly influences gastroenteropancreatic functions and exhibits orexigenic (appetite-stimulating), metabolic, cardiovascular, and antiproliferative effects. The review unequivocally underscores that ghrelin's influence extends far beyond GH regulation, acting on diverse central and peripheral receptors to mediate a wide array of physiological processes. Synthetic GHSs, developed over 20 years ago, were initially considered potential alternatives for GH deficiency treatment, but their utility as anabolic anti-aging agents for somatopause (age-related GH decline) remains unclear.
Why It Matters
This comprehensive review highlights ghrelin's multifaceted nature, demonstrating it is far more than just a GH secretagogue. Understanding ghrelin's broad actions opens new avenues for therapeutic development and drug discovery. The possibility that GHS analogues could become candidate drugs for conditions unrelated to GH secretion, such as metabolic disorders, cardiovascular diseases, or appetite regulation, is a significant implication. Future research should focus on developing ghrelin-based therapies for these diverse conditions, potentially leading to novel clinical applications.