<prompt> Which is least likely to be elevated in patients with a pheochromocytoma?Systemic aerial diastolic pressureSystemic aerial systolic pressureSerum norepinephrineIntravascular volume  <response>: Pheochromocytoma is producing Nor epinephrine Epinephrine which increases the systolic and diastolic pressure. Also Nor epinephrine would be higher DT extreme vasoconstriction the intravascular volume of the patient will be significantly reduced and not elevated. 