In the [[hypothalamus]], oxytocin is made in [[magnocellular neurosecretory cell]]s of the [[supraoptic nucleus|supraoptic]] and [[paraventricular nucleus|paraventricular]] nuclei and is stored in [[Herring bodies]] at the axon terminals in the posterior pituitary. It is then released into the blood from the [[posterior pituitary|posterior lobe]] ([[neurohypophysis]]) of the [[pituitary gland]]. These [[axons]] (likely, but [[dendrites]] have not been ruled out) have collaterals that innervate oxytocin receptors in the [[nucleus accumbens]].<ref name="Ross">{{Cite journal|author=Ross HE |title=Characterization of the Oxytocin System Regulating Affiliative Behavior in Female Prairie Voles |journal=Neuroscience |volume=162 |issue=4 |pages=892–903 |year=2009 |month=September |pmid=19482070 |doi=10.1016/j.neuroscience.2009.05.055 |pmc=2744157|author-separator=,|author2=Cole CD|author3=Smith Y|display-authors=3|last4=Neumann|first4=I.D.|last5=Landgraf|first5=R.|last6=Murphy|first6=A.Z.|last7=Young|first7=L.J.}}</ref> The peripheral hormonal and behavioral brain effects of oxytocin it has been suggested are coordinated through its common release through these collaterals.<ref name="Ross"/> Oxytocin is also made by some neurons in the paraventricular nucleus that project to other parts of the brain and to the spinal cord.<ref>{{Cite journal|author=Landgraf R, Neumann ID |title=Vasopressin and oxytocin release within the brain: a dynamic concept of multiple and variable modes of neuropeptide communication |journal=Frontiers in Neuroendocrinology |volume=25 |issue=3–4 |pages=150–76 |year=2004 |pmid=15589267 |doi=10.1016/j.yfrne.2004.05.001}}</ref> Depending on the species, oxytocin-receptor expressing cells are located in other areas, including the [[amygdala]] and [[bed nucleus]] of the [[stria terminalis]].
In the [[pituitary gland]], oxytocin is packaged in large, dense-core vesicles, where it is bound to [[neurophysin I]] as shown in the inset of the figure; neurophysin is a large [[peptide]] fragment of the larger precursor [[protein]] molecule from which oxytocin is derived by [[enzyme|enzymatic]] cleavage.
