Comparison of chromogranins A, B, and secretogranin II in human adrenal medulla and pheochromocytoma

Human phenochromocytomas were analyzed for the presence of chromogranins A and B and secretogranin II (chromogranin C). In immunohistochemistry, a positive staining of the tumor cells was observed for all three antigens. For immunoblotting, a method had to be developed which prevented proteolytic degradation of the antigens. Boiling homogenates of freeze-dried tissues achieved this and in addition, led to a significant enrichment of these secretory proteins. All three antigens could be identified in the tumor by immunoblotting. Chromogranin A and B were the major components present in about equal amounts. The relative concentration of all these antigens in the tumors was similar to those in adrenal medulla. A method involving high pressure liquid chromatography is presented which allows the separation of the human chromogranins/secretogranins.