Hormone · N-terminally truncated parathyroid hormone fragment; context-dependent PTH1R antagonist
Parathyroid hormone (7-34)
Also known as PTH(7-34)
A truncated PTH fragment used to separate PTH1R binding from activation and examine assay-dependent receptor antagonism.
- Length
- 28 amino acids
- Half-life
- Not well characterised
- Mechanism
- PTH(7-34) retains receptor-binding determinants but lacks the extreme N-terminal residues needed for efficient canonical PTH1R activation, allowing antagonism of agonist-stimulated signalling in suitable assays. Residual activity and non-canonical signalling depend on the exact sequence, terminal chemistry and receptor context.
- Studied in
- PTH1R-expressing cells, osteoblast-lineage cultures and renal cell models are used to study receptor competition, cAMP antagonism and fragment-dependent signalling.
About Parathyroid hormone (7-34)
Parathyroid hormone (7-34) is a 28-residue fragment spanning positions 7 through 34 of PTH. Relative to PTH(1-34), it lacks the first six residues but retains much of the region that contacts the extracellular domain of PTH1R. Fragment studies helped establish the distinction between receptor docking and receptor activation within the PTH sequence. The name alone does not establish species origin, amino acid substitutions or whether the C-terminus is amidated.
The fragment is commonly associated with PTH1R antagonism, particularly in assays measuring agonist-driven cAMP accumulation. Nevertheless, antagonist behaviour should not be treated as absolute across all signalling pathways. Reports involving beta-arrestin recruitment or receptor internalisation often concern specifically modified PTH(7-34) analogues rather than every peptide carrying this fragment designation. Comparative experiments therefore need an exact chemical identity, a defined receptor background and separate measurements of binding, basal activity and inhibition of an agonist response.
Laboratory notes
- Verify species sequence, substitutions and terminal chemistry; modified PTH(7-34) analogues are not interchangeable with the unmodified fragment.
- Measure activity of the fragment alone as well as its effect on a reference agonist to distinguish antagonism from residual agonism.
- Control for adsorption and peptide degradation during binding experiments, especially when working at low analytical concentrations.
Storage and reconstitution basics: storage guide.
Questions about Parathyroid hormone (7-34)
Why can PTH(7-34) bind without strongly activating cAMP signalling?
It preserves important receptor-docking determinants while removing the extreme N-terminal region that normally contributes to activation of the receptor's transmembrane core.
Is PTH(7-34) automatically a beta-arrestin-biased ligand?
No. Findings for particular substituted or amidated analogues cannot be assigned to an unspecified PTH(7-34) preparation.
Can this fragment establish that a response is mediated by PTH1R?
It can contribute supporting evidence, but receptor-expression controls, genetic approaches or additional pharmacological tools are needed for a robust assignment.
Is Parathyroid hormone (7-34) for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
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