GH secretagogue binding sites were identified in human adrenal gland, ovary, testis, myocardium, and arteries, with ghrelin confirmed as an endogenous ligand, expanding the known tissue distribution of this receptor system.
5+ tissue typesGHS receptors found in adrenal, ovary, testis, heart, and arteries — far beyond the pituitary, with ghrelin as their endogenous ligand
What the researchers found
Specific GHS binding sites identified in human adrenal, gonadal (ovary/testis), cardiac, and vascular tissues, with ghrelin confirmed as an endogenous ligand at these sites.
Why it matters
Each new tissue where GHS receptors are found suggests new biological functions and potential therapeutic applications — or safety concerns — for GH secretagogue use.
How the study worked
In-vitro binding study using 125I-Tyr-Ala-hexarelin on membrane preparations from multiple human tissue types. Ghrelin competition binding confirmed endogenous ligand activity.
What this study cannot tell us
In-vitro binding doesn't prove functional activity. Tissue availability limited to surgical specimens. The physiological role of GHS-R in each tissue remains to be determined.
How to read the evidence
Moderate evidence from comprehensive human tissue binding studies with ghrelin competition confirmation.
When this study was published
Published in 2000. The widespread distribution of ghrelin receptors has been confirmed and extended to additional tissues.
The bigger picture
The ghrelin/GHS receptor system is far more widespread than originally thought. What started as a GH-releasing pathway turns out to be a multi-organ signaling system with implications for reproduction, cardiovascular health, and endocrine function.
Questions still open
- Does ghrelin regulate reproductive function through gonadal receptors?
- Could GH secretagogue use affect fertility or adrenal function?
- Do cardiac GHS receptors mediate cardioprotective or harmful effects?
Common questions
Why are GH peptide receptors in so many tissues?
Should GH peptide users be concerned?
Read the original research
Growth hormone secretagogue binding sites in peripheral human tissues.
The Journal of clinical endocrinology and metabolism, 85(10), 3803-7
Citation
Papotti, M; Ghè, C; Cassoni, P; Catapano, F; Deghenghi, R; Ghigo, E; Muccioli, G. (2000). Growth hormone secretagogue binding sites in peripheral human tissues.. The Journal of clinical endocrinology and metabolism, 85(10), 3803-7.