Hormone · Tripeptide Hormone
Protirelin
Also known as Thyrotropin-releasing hormone (TRH)
A synthetic tripeptide identical to TRH, used as a research tool to investigate the function of the hypothalamic-pituitary-thyroid axis.
- Length
- 3 amino acids
- Half-life
- Approximately 5 minutes in plasma
- Mechanism
- This tripeptide (pGlu-His-Pro-NH2) acts on TRH receptors in the anterior pituitary to stimulate the release of thyroid-stimulating hormone (TSH) and prolactin.
- Studied in
- Laboratory models utilize protirelin to study the regulation of the hypothalamic-pituitary-thyroid (HPT) axis and its downstream signaling pathways.
About Protirelin
Protirelin is the synthetic form of thyrotropin-releasing hormone (TRH), a tripeptide with the sequence pyroglutamyl-histidyl-prolinamide. As a key regulator of the hypothalamic-pituitary-thyroid (HPT) axis, it is synthesized in the hypothalamus and acts directly on the anterior pituitary gland. Its small size and modified N- and C-termini provide some protection against rapid degradation by peptidases.
The mechanism of action involves binding to specific G-protein coupled TRH receptors on pituitary thyrotrophs and lactotrophs. This binding triggers the phospholipase C signaling pathway, leading to an increase in intracellular calcium and subsequent exocytosis of vesicles containing thyroid-stimulating hormone (TSH) and prolactin. In research contexts, protirelin is a standard reagent for assessing pituitary responsiveness and studying the molecular biology of the HPT axis. It is a reference compound with a clinical history.
Laboratory notes
- The N-terminal pyroglutamic acid and C-terminal amide make it more resistant to exopeptidases than many linear peptides.
- Protirelin is rapidly degraded in serum by specific peptidases; experiments require careful timing or the use of peptidase inhibitors.
- Store lyophilised powder at -20°C; reconstituted solutions should be used promptly or aliquoted and frozen to maintain integrity.
Storage and reconstitution basics: storage guide.
Questions about Protirelin
What is the structure of Protirelin?
It is a tripeptide with the sequence pGlu-His-Pro-NH2, making it structurally identical to endogenous TRH.
What hormones does Protirelin stimulate the release of in experimental models?
It primarily stimulates the release of thyroid-stimulating hormone (TSH) and prolactin from the anterior pituitary.
How is Protirelin different from other hypothalamic-releasing hormones?
It is significantly smaller (a tripeptide) and regulates the thyroid axis, whereas others like corticorelin (41 amino acids) regulate the adrenal axis.
Is Protirelin for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.