<prompt> Pheochromocytoma predominantly secretes which hormone: September 2007SerotoninEpinephrineNor-epinephrineDopamine  <response>: Ans. C: Nor-epinephrine Relative catecholamine levels also differ in pheochromocytomas. Most pheochromocytomas secrete norepinephrine predominantly, whereas secretions from the normal adrenal medulla are composed of roughly 85 epinephrine. Familial pheochromocytomas are an exception because they secrete large amounts of epinephrine. Thus, the clinical manifestations of a familial pheochromocytoma differ from those of a sporadic pheochromocytoma. 