Oxytocin 10 mg

One-Peptides Oxytocin 10 mg – RUO class research reagent

Oxytocin offered by One-Peptides in a package containing 10 mg of lyophilized powder is a chemical reagent intended only for research applications (Research Use Only, RUO). The product is not a medicine, dietary supplement or substance intended for any clinical use in humans or animals in non-laboratory conditions. This classification results from the provisions of Art. 3a of the Pharmaceutical Law and the guidelines of the Chief Sanitary Inspectorate regarding substances with the status of a research reagent.

The history of the discovery of oxytocin dates back to the early 20th century, when Sir Henry Dale identified the contractile activity of the posterior pituitary gland in 1906. However, a breakthrough achievement was the chemical synthesis of this peptide by Vincent du Vigneaud in 1953 – the first-ever synthesis of a polypeptide hormone, for which the Nobel Prize in Chemistry was awarded in 1955. Since then, oxytocin has become one of the most intensively studied neuropeptides in neurobiology, endocrinology and experimental pharmacology.

General description

In laboratory practice, this reagent is often compared with SELANK 10 mg and SEMAX 50 mg, to assess differences in performance profile across consistent study protocols.

Oxytocin belongs to the family of cyclic neuropeptides produced in the hypothalamus. From an organic chemistry perspective, it is a nonapeptide containing an intramolecular disulfide bond, which gives the molecule its characteristic ring structure. The scientific community’s interest in this molecule results from its multidirectional impact on signaling pathways in the nervous system and peripheral tissues – from the modulation of neuronal activity, through the regulation of smooth myocyte contractions, to the impact on neuroimmune processes observed in cellular and animal models.

Over the last two decades, the number of publications on oxytocin in the PubMed database has more than quadrupled, reflecting the growing research potential of this molecule in the context of social neurobiology, neuroendocrinology and receptor pharmacology.

What is oxytocin?

Oxytocin is a cyclic nonapeptide neurohormone with the amino acid sequence: Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2, in which cysteine ​​residues in positions 1 and 6 form a disulfide bridge (Cys1–Cys6) closing a six-amino acid ring. The C-terminal end is amidated, which is an important factor for the biological activity of the peptide.

Summary formula: C43H66N12O12S2

Molecular weight: 1007.19 g/mol

In terms of biochemical classification, oxytocin belongs to the vasopressin-oxytocin nonapeptide superfamily, which also includes arginine vasopressin (AVP). Both molecules differ in only two amino acid residues (positions 3 and 8), which is an interesting example of evolutionary divergence while maintaining a high degree of sequence homology.

The biosynthesis of endogenous oxytocin occurs in the magnocellular neurons of the paraventricular nuclei (nucleus paraventricularis) and superocular (nucleus supraopticus) hypothalamus. The precursor – preprooxytocin – undergoes proteolytic processing with the secretion of active nonapeptide and neurophysin I, and then axonal transport to the posterior lobe of the pituitary gland, from where it is released into the general circulation.

Structure and physicochemical properties

Primary structure and modifications

The Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2 sequence with a Cys1–Cys6 disulfide bridge forms a rigid six-part ring, while the C-terminal tripeptide tail (Pro-Leu-Gly-NH2) retains greater conformational freedom. Amidation of the C-terminus is necessary for full binding activity to the OXTR receptor – deamidated analogues show significantly reduced receptor affinity in competitive radioligand binding assays.

Stability

The lyophilized form of oxytocin is highly stable at -20 °C when stored in an inert gas atmosphere (argon or nitrogen). The main degradation pathways include: (1) oxidation of the disulfide bridge, (2) deamidation of Asn and Gln residues, (3) isomerization of Asp. In aqueous solution, the peptide shows the highest stability in the pH range 3.0–5.0.

Solubility

Oxytocin is soluble in distilled water and aqueous solutions with low pH (acetic acid 0.1%). The solubility in phosphate buffer (PBS, pH 7.4) is approximately 1 mg/ml. Dissolution in highly polar organic solvents is not recommended (DMSO is acceptable as a co-solvent at low concentrations).

Storage conditions

Lyophilisate: -20 °C, tightly closed vessel, protected from light and moisture. After reconstitution: aliquot solution, stored at -80 °C, avoid repeated freezing and thawing. The stability of the working solution at 4 °C is up to 7 days.

Mechanism of action at the molecular level

Oxytocin exerts its biological effects primarily by binding to the oxytocin receptor (OXTR) – a G protein-coupled receptor of the Gq/11 class. OXTR activation leads to the activation of a signaling cascade including the following stages:

1. Activation of phospholipase C-beta (PLC-beta) — hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2)
2. Generation of secondary relays — inositol triphosphate (IP3) and diacylglycerol (DAG)
3. Mobilization of intracellular calcium — IP3 binds IP3R receptors on the endoplasmic reticulum, causing the release of Ca2+ ions into the cytosol
4. Activation of protein kinase C (PKC) — DAG together with Ca2+ activates PKC isoforms, modulating the phosphorylation of target proteins

In neurons of the central nervous system, oxytocin also modulates GABAergic and glutamatergic signaling pathways. Studies on rodent brain sections have shown that oxytocin enhances GABAergic transmission in the amygdala, which correlates with the observed anxiolytic-like effects in behavioral tests.

It is worth emphasizing that OXTR has a heterogeneous tissue distribution – expression occurs both in the central nervous system (hypothalamus, amygdala, nucleus accumbens, prefrontal cortex) and in peripheral tissues (myometrium, mammary gland, kidneys, heart, adipose tissue). This diversity of expression is the basis for the multidirectionality of effects observed in studies.

Applications in scientific research

Research on social behavior in animal models

Prairie voles (Microtus ochrogaster) constitute a classic animal model for studying the role of oxytocin in the formation of partner bonds. Administration of oxytocin to the nucleus accumbens of female prairie voles accelerated the formation of partner preference, while administration of an OXTR antagonist blocked this process. These studies provided significant data on the relationship between oxytocinergic signaling and dopaminergic activity in the reward system.

Models of smooth muscle contractility

In isolated myometrium preparations, oxytocin induces phasic contractions in a concentration-dependent manner. These tests are carried out on isolated tissue strips in organ systems (organ bath), which enables precise determination of the range of working concentrations and interactions with antagonists (e.g. atosiban). These models are used to study the mechanisms of regulation of uterine contractility at the cellular level.

Neuroimmune models

Observations in microglial cell cultures indicate that oxytocin modulates lipopolysaccharide (LPS)-induced microglial activation. In vitro, exposure of microglial cells to oxytocin reduced the release of proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6), suggesting research potential in the context of neuroinflammation models.

Myoepithelial cells of the mammary gland

In cultures of primary mammary myoepithelial cells, oxytocin induces the contraction of these cells by mobilizing intracellular Ca2+ – a process mechanistically similar to myometrial contraction. These models allow examining differences in tissue sensitivity to oxytocin depending on the density of OXTR receptors.

Behavioral tests in rodents

In rodent models of drug-like anxiolytic effects (elevated plus maze test – EPM; light/dark chamber test – light-dark box) administration of oxytocin into the central nervous system of C57BL/6 mice or Wistar rats led to an increase in time spent in the open arms (EPM) and in the light chamber. These effects were blocked by pretreatment with an OXTR antagonist (L-368,899), confirming the involvement of the oxytocin receptor in the observed behavioral phenotype.

Summary

Oxytocin 10 mg from One-Peptides is a high-purity research reagent in the form of a lyophilized powder, intended for reconstitution in laboratory conditions. This molecule – a cyclic nonapeptide with a mass of 1007.19 g/mol with a Cys1–Cys6 disulfide bridge – remains one of the most intensively studied neuropeptides in the context of receptor signaling (OXTR/Gq/11/PLC/IP3/Ca2+), models of social behavior, smooth muscle contractility and neuroimmunology.

The product is intended for research use only (Research Use Only). It is not a medicine or food. All data presented in this description comes from published scientific research and does not constitute claims about health properties.

Research conclusions

• Oxytocin activates the Gq/11 protein-coupled OXTR receptor, triggering the PLC/IP3/DAG cascade and intracellular Ca2+ mobilization.
• In animal models (Microtus ochrogaster) a relationship between oxytocinergic signaling and the formation of partner preference was demonstrated
• Isolated myometrium preparations exhibit oxytocin-induced phasic contractions in a concentration-dependent manner
• Microglial cell cultures exposed to oxytocin showed reduced levels of proinflammatory cytokine release after LPS stimulation.
• In EPM tests i light-dark box in rodents, anxiolytic-like effects were observed after central administration of oxytocin, blocked by an OXTR antagonist

RUO category: Oxytocin collects products associated with this molecule.