The ghrelin receptor GHS-R1a plays critical roles in metabolism, neurotransmission, and behavior, making it a promising drug target for obesity and other conditions.
Multi-system peptide targetThe ghrelin receptor GHS-R1a regulates metabolism, neurotransmission, and behavior, with multiple agonist and antagonist drugs developed for clinical testing
What the researchers found
The review covers the ghrelin receptor GHS-R1a from discovery to therapeutic potential:
- GHS-R1a was expression-cloned at MERCK laboratories in the early 1990s using synthetic GH secretagogue molecules
- The receptor is expressed in the brain and throughout the body
- Its endogenous ligand, the peptide hormone ghrelin, regulates metabolism, neurotransmission, and behavior
- Multiple GHS-R1a agonists and antagonists are available, with some showing promising clinical results
- A second receptor form (GHS-R1b) also exists, though its function is less well characterized
- Rodent studies have revealed potential roles for receptor modulation in obesity, glucose homeostasis, and other conditions
Why it matters
The ghrelin receptor sits at the crossroads of hunger, metabolism, and brain function. Understanding how to pharmacologically manipulate this receptor could lead to treatments for obesity, cachexia (wasting), growth hormone deficiency, and potentially neurological conditions — making it one of the most versatile peptide hormone drug targets.
How the study worked
This is a book chapter-style review synthesizing the literature on ghrelin receptor biology, pharmacology, and therapeutic targeting from the receptor's discovery through 2013.
What this study cannot tell us
As a 2013 review chapter, it does not include more recent discoveries about ghrelin receptor signaling complexity, biased agonism, or receptor dimerization. Clinical trial results available at the time were limited. The role of GHS-R1b remains poorly characterized.
How to read the evidence
This is a review chapter providing a comprehensive overview of ghrelin receptor biology and pharmacology. It synthesizes existing evidence without generating new data.
When this study was published
Published in 2013, this review provides foundational context for understanding the ghrelin system. Significant advances in ghrelin receptor pharmacology have occurred since, but the core biology covered remains accurate.
The bigger picture
The ghrelin system has become central to our understanding of appetite regulation and energy balance. This review captured the field at a key transition point — from basic receptor biology to clinical applications. Since its publication, ghrelin receptor pharmacology has continued to evolve, with ongoing clinical trials for obesity, gastroparesis, and growth hormone disorders.
Questions still open
- Can ghrelin receptor antagonists be effective obesity treatments without the side effects of appetite suppression?
- How does the GHS-R1b receptor variant modulate the effects of GHS-R1a signaling?
- Could ghrelin receptor modulators be useful for treating conditions beyond obesity, such as addiction or cognitive decline?
Common questions
What is the ghrelin receptor and why is it important?
Are there drugs that target the ghrelin receptor?
Read the original research
The ghrelin receptors (GHS-R1a and GHS-R1b).
Endocrine development, 25, 5-15
Citation
Albarrán-Zeckler, Rosie G; Smith, Roy G. (2013). The ghrelin receptors (GHS-R1a and GHS-R1b).. Endocrine development, 25, 5-15. https://doi.org/10.1159/000346042