Chromogranin B is a tyrosine-sulfated secretory protein found in a wide variety of peptidergic endocrine cells. Chromogranin functions as a neuroendocrine secretory granule protein which may be the precursor for other biologically active peptides.Secretoneurin is involved in chemotaxis of monocytes and eosinophils (comparable in potency to IL8) and endothelial cells and in regulation of endothelial cell proliferation.Highest secretoneurin levels are found in anterior pituitary, followed by adrenal medulla and posterior pituitary hypothalamus (2- to 6-fold lower levels in other brain regions investigated). Secretoneurin has been shown to have potent angiogenic activity in vivo in mouse cornea model and in vitro in a 3-dimensional gel.