Pituitary stalk Pituitary stalk The pituitary stalk (also known as the infundibular stalk, Fenderson's funnel, or simply the infundibulum) is the connection between the hypothalamus and the posterior pituitary. The floor of the third ventricle is prolonged downward as a funnel-shaped recess—the infundibular recess—into the infundibulum, where the apex of the pituitary is attached. It passes through the dura mater of the diaphragma sellae as it carries axons from the magnocellular neurosecretory cells of the hypothalamus down to the posterior pituitary where they release their neurohypophysial hormones, oxytocin and vasopressin, into the blood. This connection is called the hypothalamo-hypophyseal tract or hypothalamo-neurohypophyseal
Pituitary adenylate cyclase-activating peptide Pituitary adenylate cyclase-activating peptide Pituitary adenylate cyclase-activating polypeptide also known as PACAP is a protein that in humans is encoded by the "ADCYAP1" gene. PACAP is similar to vasoactive intestinal peptide. One of its effects is to stimulate enterochromaffin-like cells. It binds to vasoactive intestinal peptide receptor and to the PACAP receptor. This gene encodes adenylate cyclase-activating polypeptide 1. Mediated by adenylate cyclase-activating polypeptide 1 receptors, this polypeptide stimulates adenylate cyclase and subsequently increases the cAMP level in target cells. Adenylate cyclase-activating polypeptide 1 not only is a hypophysiotropic hormone (i.e. a substance that induces activity in the hypophysis) but