Chromogranin A or parathyroid secretory protein 1 (gene name CHGA) is a member of the chromogranin/secretogranin (granins) family of neuroendocrine secretory proteins, i.e. it is located in secretory vesicles of neurons and endocrine cells. Examples of cells producing chromogranin A are chromaffin cells of the adrenal medulla, enterochromaffin-like cells and beta cells of the pancreas. It is elevated in pheochromocytomas.
Chromogranin A is the precursor to several functional peptides including vasostatin, pancreastatin, catestatin and parastatin. These peptides negatively modulate the neuroendocrine function of the releasing cell (autocrine) or nearby cells (paracrine). Other peptides derived from chromogranin A with uncertain function include chromostatin, WE-14 and GE-25.
Chromogranin A might promote the generation of secretory granules. It is used as an indicator for pancreas and prostate cancer. It might play a role in early neoplasic progression. It is also elevated in diabetes. Chromogranin A is cleaved by an endogenous prohormone convertase to produce several peptide fragments. See chromogranin A GeneRIFs for references.