Ghrelin and synthetic GH secretagogues (hexarelin, EP-80317) protected rat hearts from ischemia-reperfusion injury, improving contractile recovery through effects on coronary perfusion pressure.
Peptides > non-peptidePeptide GH secretagogues outperformed MK-677 for cardiac protection — the heart's receptor prefers peptide ligands
What the researchers found
Ghrelin, hexarelin, and EP-80317 improved cardiac contractile recovery after ischemia in isolated rat hearts, with effects on coronary perfusion pressure, while MK-677 showed less cardioprotection — suggesting peptide GHS are preferred cardiac protectants.
Why it matters
Demonstrating that peptide GH secretagogues are better cardioprotectants than non-peptide MK-677 guides drug selection for cardiac applications and suggests a peptide-preferring cardiac receptor.
How the study worked
In-vitro isolated rat heart (Langendorff) study. Ghrelin, hexarelin, EP-80317, and MK-677 tested before or during ischemia-reperfusion. Cardiac contractile function and coronary perfusion pressure measured.
What this study cannot tell us
Isolated rat heart model. The specific cardiac receptor mediating protection was not definitively identified. Short-term ischemia protocol.
How to read the evidence
Preliminary in-vitro evidence from isolated heart experiments comparing multiple GH secretagogues for cardioprotection.
When this study was published
Published in 2003. The cardiac GH secretagogue receptor (linked to CD36) has been further characterized with peptide preference confirmed.
The bigger picture
Not all GH secretagogues are equal for cardiac protection. The peptide compounds' superiority suggests the cardiac receptor (possibly CD36) has different ligand preferences than the pituitary GHS-R.
Questions still open
- Does the cardiac receptor prefer peptide over non-peptide ligands?
- Could hexarelin or EP-80317 be developed specifically as cardiac drugs?
- Does the coronary vascular effect explain the contractile protection?
Common questions
Which GH peptides protect the heart best?
Why would the heart prefer peptide GH drugs?
Read the original research
Effect of ghrelin and synthetic growth hormone secretagogues in normal and ischemic rat heart.
Basic research in cardiology, 98(6), 401-5
Citation
Frascarelli, Sabina; Ghelardoni, Sandra; Ronca-Testoni, Simonetta; Zucchi, Riccardo. (2003). Effect of ghrelin and synthetic growth hormone secretagogues in normal and ischemic rat heart.. Basic research in cardiology, 98(6), 401-5.