Oxytocin

Oxytocin Peptide Overview

Oxytocin is a potent nonapeptide, consisting of a sequence of nine amino acids, primarily synthesized within the paraventricular and supraoptic nuclei of the hypothalamus. It is subsequently transported to and secreted by the posterior pituitary gland into systemic circulation. Beyond its neurological origins, oxytocin is synthesized in peripheral tissues including the placenta, interstitial cells of the testes, and the ovaries. As a peptide hormone, it is initially produced as a larger inactive precursor protein, prepro-oxytocin, which undergoes enzymatic cleavage to reach its biologically active form.

While historically recognized as a neurohypophyseal hormone governing reproductive functions, contemporary research identifies oxytocin as a ubiquitous signaling molecule. Production sites have been identified in the retina, adrenal glands, thymus, and pancreas, suggesting that its physiological influence extends far beyond the endocrine system. It acts as both a systemic hormone and a central neurotransmitter, facilitating complex interactions between the body and the brain.

Oxytocin Peptide Structure

The primary structure of Oxytocin is a cyclic peptide. It features a disulfide bridge between two cysteine residues, creating a six-member ring with a three-member C-terminal tail.

Structure Solution Formula: C43H66N12O12S2

Amino Acid Sequence: Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2

Property

Specification

Molecular Weight

1007.2 g/mol

Peptide Purity

Greater than 98 percent

Physical Appearance

White lyophilized powder

Biological Half-Life

3 to 5 minutes (systemic)

Target Receptor

Oxytocin Receptor (OXTR)

Oxytocin Peptide Research

Oxytocin in Wound Healing

Oxytocin demonstrates significant immunomodulatory properties, specifically influencing the expression of pro-inflammatory cytokines. Research indicates that elevated oxytocin levels correlate with an accelerated rate of re-epithelialization and collagen deposition. In controlled studies of social cohorts, higher endogenous oxytocin levels were associated with a marked increase in the speed of wound repair. Conversely, social stress and hostility—which suppress oxytocin release—can delay the healing process by as much as 40 percent. This delay is often accompanied by lower concentrations of IL-6 and tumor necrosis factor at the injury site.

Studying Oxytocin in Cardiovascular Risk

Research suggests that oxytocin serves a cardioprotective role by modulating systemic inflammation and metabolic health. It has been observed to improve glucose metabolism, lower blood pressure, and reduce adiposity. In models of atherosclerosis, a deficiency in oxytocin receptor expression is often linked to the progression of arterial plaque. Administering oxytocin during myocardial ischemic events has shown promise in protecting cardiomyocytes from apoptosis. Furthermore, long-term treatment may prevent dilated cardiomyopathy by preconditioning cardiac stem cells for more effective tissue regeneration.

Diabetes Management

Oxytocin enhances insulin sensitivity and promotes glucose uptake within skeletal muscle tissue. In murine models, the peptide has been shown to reduce fat accumulation and mitigate the effects of dyslipidemia. Research highlights that oxytocin’s metabolic benefits are most pronounced in obese or insulin-resistant subjects, where it significantly improves HbA1c levels. In clinical trials, intranasal administration has resulted in weight loss and improved glycemic control, suggesting its utility in managing metabolic syndrome.

Oxytocin and Old Muscle

Aging is characterized by a decline in the regenerative capacity of skeletal muscle, often resulting in sarcopenia. Research from the University of California, Berkeley, indicates that this decline is partially driven by a reduction in oxytocin signaling. Supplementing aged biological systems with oxytocin has been shown to restore muscle stem cell function to approximately 80 percent of the capacity seen in younger subjects. This suggests that oxytocin is a critical factor in maintaining tissue homeostasis throughout the lifespan.

Article Author

This review was compiled and organized by Dr. Sue Carter, Ph.D., an esteemed behavioral neurobiologist known globally for her groundbreaking studies on oxytocin and social attachment. Dr. Carter’s research has been pivotal in redefining oxytocin’s dual role as both a hormone and a neuromodulator.

Scientific Journal Author

Dr. Thomas R. Insel, M.D., a distinguished neuroscientist and former Director of the National Institute of Mental Health (NIMH), is recognized for his foundational research on oxytocin, vasopressin, and affiliative behavior.

Reference Citations

1. du Vigneaud V, et al. The synthesis of an octapeptide amide with the hormonal activity of oxytocin. J Am Chem Soc. 1953;75(19):4879-4880.
2. Gimpl G, Fahrenholz F. The oxytocin receptor system: structure, function, and regulation. Physiol Rev. 2001;81(2):629–683.
3. Insel TR. The challenge of translation in social neuroscience: a review of oxytocin, vasopressin, and affiliative behavior. Neuron. 2010;65(6):768-779.
4. Carter CS. Oxytocin pathways and the evolution of human behavior. Annu Rev Psychol. 2014;65:17-39.
5. Heinrichs M, et al. Neuroendocrine mechanisms of stress and oxytocin. Biol Psychiatry. 2009;65(9):774-782.
6. Neumann ID, et al. Central oxytocin mechanisms in stress and anxiety. Prog Brain Res. 2008;170:143–159.
7. Lee HJ, et al. Oxytocin receptor signaling in social and emotional behavior. Prog Neurobiol. 2009;88(2):127-151.
8. Leng G, Sabatier N. Measuring oxytocin and vasopressin: bioassays and immunoassays. J Neuroendocrinol. 2016;28(4).
9. Meyer-Lindenberg A, et al. Oxytocin and human social behavior. Science. 2011;333(6039):1148-1151.
10. Peters S, et al. Oxytocin and the stress response system. Front Neuroendocrinol. 2018;51:14-30.

Storage

Storage Instructions

All products are produced through a lyophilization (freeze-drying) process, which preserves stability during shipping for approximately 3 to 4 months. After reconstitution with bacteriostatic water, peptides must be stored in a refrigerator (below 4 degrees Celsius) to maintain effectiveness. Once mixed, they remain stable for up to 30 days.

Best Practices For Storing Peptides

For long-term preservation over several months or years, peptides should be stored in a freezer at -80 degrees Celsius. It is essential to minimize freeze-thaw cycles, as repeated temperature fluctuations can accelerate degradation.

Preventing Oxidation and Moisture Contamination

Allow the vial to reach room temperature before opening to prevent condensation. Peptides containing Cysteine or Methionine are especially sensitive to air oxidation and should be resealed promptly after use.

Storing Peptides In Solution

Peptide solutions have a shorter shelf life than lyophilized forms. If storage in solution is required, use sterile buffers with a pH between 5 and 6.

Peptide Storage Containers

High-quality glass vials provide the best stability and chemical inertness. While often shipped in plastic for safety, transferring to glass for long-term storage is acceptable.

Peptide Storage Guidelines: General Tips

• Store in a cold, dry, and dark environment.
• Avoid repeated freeze-thaw cycles.
• Protect from light exposure.
• Keep lyophilized until immediate use is required.