Oxytocin peptide Overview Oxytocin is a peptide hormone. Secreted by the posterior pituitary. It is composed of paraventricular nucleus and supraoptic nucleus. It is composed of nine amino acids. They are transported to the neurohypophysis at a rate of 2-3 mm per day. The methionine residues at “1” and “6” sites form a 6-peptide ring structure in the form of …