title: Adrenergic receptor hyperactivity--a cause for pseudopheochromocytoma?
abstract: Two patients with classical signs and symptoms of pheochromocytoma, are described. In these two patients the 24-hr urinary excretion of dopamine, norepinephrine, epinephrine and their metabolites were normal or low, both in basal states or after attacks (spontaneous or provoked). However, the 24-hr urinary excretion of cyclic AMP was exceedingly high in one patient (13000 nmol/gm creatinine), and elevated in the second (5920 nmol/gm creatinine). Both patients were benefited by treatment with a combination of alpha and beta adrenergic blocking drugs. The first patient, after stopping treatment, developed hypertensive crisis and died. Post-mortem examination did not detect a pheochromocytoma or any other abnormality which could explain the excessively elevated cyclic AMP. In the second patient, extensive X-ray and CT examinations were negative for pheochromocytoma. A hypothesis is developed linking the symptoms and biochemical findings of both patients to an abnormality of the adrenergic receptor.
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000175:diagnosis*; D002395:Catecholamines / Q000652:urine; D000242:Cyclic AMP / Q000652:urine; D003951:Diagnostic Errors; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010643:Phenoxybenzamine / Q000627:therapeutic use; D010673:Pheochromocytoma / Q000175:diagnosis*; D011433:Propranolol / Q000627:therapeutic use; D011941:Receptors, Adrenergic / Q000502:physiology*
chemical_list: D002395:Catecholamines; D011941:Receptors, Adrenergic; D010643:Phenoxybenzamine; D011433:Propranolol; D000242:Cyclic AMP