The principal secretions of the posterior pituitary are the peptides oxytocin (uterus-contracting hormone/milk let-down hormone) and vasopressin (ADH); both are synthesised as part of prohormones that include distinctive neurophysins.
After packaging, the peptides are transported as granules, by axoplasmic flow, to the nerve terminals in the posterior pituitary where they are released directly into the circulation to act as classical neurohormones on distant target sites.
