Human ghrelin is a 28-amino-acid acylated peptide hormone and endogenous agonist of GHSR1a. The mature peptide carries an n-octanoyl group at Ser3, a post-translational modification that is central to its canonical receptor activity.

Human ghrelin provides a defined ligand for studies connecting gastric endocrine signaling with pituitary growth hormone release, hypothalamic pathways, energy homeostasis and class A GPCR pharmacology.

Product Information

A Lipid-Modified Peptide Hormone

The fatty-acid modification at Ser3 is not an accessory label. It is part of the biologically relevant ghrelin structure and strongly influences recognition by the growth hormone secretagogue receptor.

This feature distinguishes ghrelin from most classical peptide hormones and creates a useful model for studying how covalent lipidation changes GPCR ligand recognition.

Growth Hormone and GHSR1a Signaling

Ghrelin activates GHSR1a in pituitary and hypothalamic systems and can stimulate growth hormone secretion through a signaling pathway that complements, but is molecularly distinct from, the GHRH receptor pathway.

Receptor activation can be studied through intracellular calcium mobilization and other downstream signaling readouts. In vivo endocrine responses also depend on the interaction between ghrelin, somatostatin and GHRH systems.

Human Ghrelin Molecular Diversity

Human stomach and plasma contain more than one ghrelin-related molecular form. In addition to the major 28-residue octanoylated peptide, studies have identified des-acyl, alternative fatty-acyl and shorter 27-residue forms.

We recommend specifying the exact acylation state, chain length and peptide sequence whenever results from different ghrelin preparations are compared.

Human Versus Rat Ghrelin

Human and rat ghrelin share the conserved N-terminal sequence and Ser3 octanoylation required for receptor activation but differ at residues 11 and 12.

This high degree of conservation allows useful cross-species comparisons while still making exact peptide identity relevant for quantitative pharmacology.

For a species-matched rodent ligand, researchers can review Rat Ghrelin.

Research Applications

Human ghrelin can support GHSR1a binding and signaling studies, pituitary GH-release research, metabolic and feeding experiments, receptor mutagenesis, peptide acylation studies and comparison with minimal ghrelin-derived ligands.

Related endocrine research peptides are available in our Growth Hormone Peptides collection.

Analytical Considerations

Correct Ser3 octanoylation should be evaluated together with peptide identity and purity. A preparation containing the correct 28-residue backbone but an incorrect acylation state is not chemically equivalent to mature active ghrelin.

Researchers requiring batch-specific confirmation can use our Peptide Quality Control capabilities for HPLC and mass-spectrometric characterization.

Frequently Asked Questions

What is unusual about human ghrelin?

Its Ser3 residue carries an n-octanoyl fatty-acid modification that is important for canonical GHSR1a activation.

Is human ghrelin the same as des-acyl ghrelin?

No. Des-acyl ghrelin lacks the Ser3 fatty-acid group and has markedly different activity at the canonical ghrelin receptor.

Is ghrelin C-terminally amidated?

No. The human 28-residue ghrelin sequence has a free C-terminal carboxyl group.

Can custom acylated ghrelin analogs be prepared?

Alternative fatty-acid modifications, point mutations and truncated ghrelin analogs can be evaluated through Chemical Peptide Synthesis.

Research Use Only.