Developments in ghrelin biology and potential clinical relevance

Area of Science:

• Endocrinology
• Neuroscience
• Molecular Biology

Background:

• The growth hormone secretagogue receptor (GHS-R) is a key mediator of growth hormone release.
• Ghrelin, a peptide hormone, is a primary endogenous ligand for the GHS-R.
• Understanding the GHS-R and its ligands is crucial for metabolic and endocrine research.

Purpose of the Study:

• To review recent advancements in the understanding of ghrelin and GHS-R physiological roles.
• To explore the implications of ghrelin's effects on new pathways for potential clinical applications.
• To summarize the characterization and cloning of the GHS-R.

Main Methods:

• Exploitation of the spiropiperidine MK0677 for GHS-R characterization and cloning.
• Identification of ghrelin and adenosine as natural GHS-R ligands.
• Gene targeting (Ghsr knockout) to elucidate ghrelin's functions.

Main Results:

• The GHS-R was successfully cloned and characterized.
• Ghrelin's growth hormone-releasing and orexigenic effects were confirmed to be Ghsr-dependent.
• Ghrelin's orexigenic signaling involves neuropeptide Y and agouti-related peptide neurons.
• Ghrelin influences the thymus and inflammatory cytokine pathways.

Conclusions:

• Ghrelin's physiological roles are diverse and mediated through the GHS-R.
• Ghrelin's impact on inflammatory pathways suggests potential therapeutic applications.
• Further research into ghrelin and GHS-R may offer insights into age-associated disorders like metabolic disease and sarcopenia.