Pleiotrophin (PTN)

Pleiotrophin was initially recognized as a neurite outgrowth-promoting factor present in rat brain around birth and as a mitogen toward fibroblasts isolated from bovine uterus tissue. Together with midkine these growth-factors constitute a family of secreted heparin-binding proteins now known as the Neurite Growth-promoting Factor (NEGF) family. During embryonic and early postnatal development, Pleiotrophin is expressed in the central and peripheral nervous system and also in several non-neural tissues, notably lung, kidney, gut and bone. Pleiotrophin is also expressed by several tumor cells and is thought to be involved in tumor angiogenesis. In the adult central nervous system.  Pleiotrophin is expressed in an activity-dependent manner in the hippocampus, where it can suppress long term potentiation induction.