Ghrelin receptor
/GHREL-in receptor/
Also known as: growth hormone secretagogue receptor, GHSR, GHSR1a
Definition
The ghrelin receptor (officially GHSR1a) is a G-protein-coupled receptor that binds ghrelin, a 28-amino-acid peptide hormone synthesized predominantly in the gastric mucosa. Ghrelin is known as the 'hunger hormone' due to its role in stimulating appetite and food intake via hypothalamic centres that control energy balance. The ghrelin receptor is widely distributed in the central and peripheral nervous systems, the pituitary gland, and various peripheral tissues. Ghrelin receptor agonists—both natural ghrelin itself and synthetic peptide analogues—have been extensively researched to understand how ghrelin signalling influences feeding behaviour, GH secretion, glucose homeostasis, and other metabolic parameters. The ghrelin receptor acts synergistically with other appetite-regulating systems and integrates signals about energy status.
Ghrelin secretion is regulated by feeding state, circulating glucose, and other metabolic signals, creating dynamic hourly and circadian patterns. Ghrelin receptor agonists examined in research have been characterized for their ability to mimic these patterns and their effects on integrated physiological responses. Some compounds show preferential GH-releasing activity (through ghrelin receptor signalling in the pituitary), while others preferentially affect appetite centres in the hypothalamus, depending on tissue distribution and local receptor density.
Research comparing ghrelin receptor agonists to GHRH analogues and combination therapy has examined whether synergistic effects on GH secretion exist and how these compounds influence body composition, energy expenditure, and metabolic markers. Preclinical and clinical studies have evaluated the safety and efficacy profiles of these compounds, with particular attention to potential effects on glucose metabolism, cardiovascular function, and hormonal axes beyond growth hormone.