Oxytocin Another Name: Oxtocin CAS: 50-56-6 MF: C43H66N12O12S2 MW: 1007.19 EINECS: 200-048-4 What is oxytocin, and what does it do?Oxytocin is a hormone that is made in the brain, in the hypothalamus, and it is transported to, and secreted by, the pituitary gland, which is located at the base of the brain.1 Chemically it is known as a nonapeptide (a peptide containing nine amino acids), and biologically, as a neuropeptide. It acts both as a hormone and as a brain neurotransmitter.