Free acid form of oxytocin, which is a hormone involved in many aspects of mammalian reproduction as well as other physiological processes such as bond pairing and cardiovascular homeostasis.

Oxytocin is a hormone that is produced by the hypothalamus and secreted by the pituitary gland. It is used in pharmacology to treat various conditions, such as postpartum haemorrhage, uterine contractions, labour induction, and to stimulate milk production. Oxytocin has been shown to activate G-protein coupled receptors (GPCRs) and ion channels. The oxytocin receptor is a GPCR that regulates social behaviours. This receptor can be activated by oxytocin via a series of reactions and signaling pathways. Oxytocin also stimulates the production of certain proteins, such as cAMP response element binding protein (CREB). Oxytocin has been used as an antibody for immunohistochemical studies on animal tissues and cell cultures.