Figure 4.Schematic overview of the post-translational processing of the Vasopressin-neurophysin II gene product. Sequential modification of the VP-NPII preprohormone in endoplasmic reticulum and golgi lead to trafficking through the regulated secretory pathway and ultimately release from neurosecretory vesicles in the posterior pituitary. A small amount of partially processed precursor is released through the constitutive secretory pathway. OT is processed in a similar manner.