Oxytocin
Nonapeptide hormone · cyclic disulfide-bridged
Identifier graph
Cross-references to canonical chemistry knowledge graphs. Each binding is the same identity used in PubMed-indexed literature.
- CAS Registry Number
- 50-56-6 · CAS Common Chemistry
- InChIKey
-
XNOPRXBHLZRZKH-DSZYJQQASA-N - PubChem CID
- CID 439302
- Wikidata
- Q169960
- ChEMBL
- CHEMBL4303358
- Molecular formula
C43H66N12O12S2- Molecular weight
- 1007.19 g/mol
- Peptide sequence
Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2- IUPAC name
- (2S)-1-[(4R,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-[(2S)-butan-2-yl]-16-[(4-hydroxyphenyl)methyl]-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentazacycloicosane-4-carbonyl]-N-[(2S)-1-[(2-amino-2-oxoethyl)amino]-4-methyl-1-oxopentan-2-yl]pyrrolidine-2-carboxamide
What is Oxytocin?
Oxytocin is a 9-residue cyclic peptide hormone synthesised in the magnocellular neurons of the supraoptic and paraventricular nuclei of the hypothalamus and released from the posterior pituitary. Its sequence is Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂, with an intramolecular disulfide bridge between Cys1 and Cys6 producing the characteristic 6-residue ring. Oxytocin is MHRA-licensed in the UK as a prescription medicine for obstetric indications (Syntocinon®, Pitocin®).
CAS 50-56-6, molecular formula C₄₃H₆₆N₁₂O₁₂S₂, molecular weight 1007.19 g/mol. Wikidata QID Q169960, PubChem CID 439302, ChEMBL ID CHEMBL4303358.
Mechanism of action
Oxytocin binds the oxytocin receptor (OXTR) — a class-A G-protein-coupled receptor expressed on uterine smooth muscle, myoepithelial cells of the mammary gland, and broadly throughout the central nervous system. Peripheral OXTR activation produces uterine contraction (the basis of its obstetric use) and milk-let-down. Central OXTR activation modulates social-bonding behaviours, anxiety responses and stress-axis regulation.
Research context
Investigated in clinical use for obstetric induction and post-partum haemorrhage management. Research applications focus on central oxytocin function — social bonding, autism- spectrum-disorder research, anxiety and stress response, and neuroendocrine regulation.
Analytical specifications
Every batch of Oxytocin supplied by NMChem is characterised by reversed-phase HPLC for purity determination and by mass spectrometry for identity confirmation. Certificate of Analysis (COA) documents are issued per batch and made available on request.
Identity is confirmed by electrospray-ionisation mass spectrometry (ESI-MS); the observed mass falls within ±2 Da of the theoretical monoisotopic mass calculated from the residue sequence. Purity is determined by reversed-phase HPLC on a C18 column with a trifluoroacetic-acid-modified water/acetonitrile gradient and reported as the area-under-curve percentage of the main peak at 214 nm. NMChem specification is ≥99% main peak. Material ships as lyophilised powder and must be reconstituted in sterile water or bacteriostatic water immediately before use.
Note: Oxytocin's disulfide bridge is essential to activity. Identity by ESI-MS reflects the cyclised (disulfide-bridged) form. Improper handling can reduce the disulfide; specifications are reported for the intact cyclic form.
UK regulatory status
Oxytocin is an MHRA-licensed prescription medicine in the UK (Syntocinon®, Pitocin®) for obstetric indications. NMChem supplies oxytocin as a research-grade reference standard for laboratory characterisation and is not a substitute for the pharmaceutical preparation. The research-grade product must not be used for human or veterinary administration. Buyers are responsible for compliance with the Human Medicines Regulations 2012 and any institutional controlled-substance policies.
Research literature
Selected peer-reviewed publications from PubMed referencing this compound.
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The Oxytocin Receptor: From Intracellular Signaling to Behavior.
Jurek B et al. · Physiological reviews · 2018
PubMed PMID 29897293 -
Control of lipolysis by a population of oxytocinergic sympathetic neurons.
Li E et al. · Nature · 2024
PubMed PMID 38093006 -
Oxytocin Improves Intracerebral Hemorrhage Outcomes by Suppressing Neuronal Pyroptosis and Mitochondrial Fission.
Yang M et al. · Stroke · 2023
PubMed PMID 37317879
Related compounds
Other research compounds in adjacent mechanism classes or commonly used alongside Oxytocin.
Frequently asked questions about Oxytocin
Is research-grade oxytocin the same as Syntocinon?
Get research-grade Oxytocin from NMChem
UK supplier · HPLC and MS verified · Per-batch Certificate of Analysis · Tracked Royal Mail dispatch.