Oxytocin

Oxytocin is a nonapeptide — nine amino acids, Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2 — whose two cysteines form a disulfide bridge that closes six of those residues into a ring and leaves a three-residue tail. In mammals it is synthesized in the hypothalamus; the research-grade material here is made by solid-phase synthesis to the same sequence. It differs from vasopressin at only two positions, which is why receptor selectivity is a recurring problem in the literature rather than a settled question.

Shipped as a lyophilized powder in a sealed 5 mg glass vial. The disulfide ring is the labile part of the molecule, so the powder stays dry, cold and sealed. Supplied for laboratory research use only.

Oxytocin is studied heavily as a receptor ligand and as a structure-activity problem. Areas of study include:

• Oxytocin receptor pharmacology — a class A GPCR signaling through Gq and phospholipase C, read out as intracellular calcium flux.
• Selectivity against vasopressin receptors, where a two-residue difference produces substantial cross-reactivity and complicates interpretation.
• Structure-activity relationships of the cyclic ring — which substitutions preserve binding and which collapse it.
• Analog design for peptidase resistance, since the native peptide is cleared rapidly.
• Receptor distribution mapping in tissue sections across species.

Supplied as a characterized reagent. We make no claim about behavioural or physiological outcomes.