Localization of Pheochromocytoma by Measurement of Plasma Cyclic AMP

To the Editor: Recent advances in radiographic and biochemical techniques have dramatically improved the ability to locate pheochromocytomas, but some tumors may still elude these methods, especially when they are small and located in unusual sites or are biochemically inactive. Our experience indicates that ghicagon-induced changes in plasma cyclic AMP may be of assistance in the process of localization. A 35-year-old man had recurrent paroxysms of throbbing headache, palpitation, and transient hypertension occurring two to three times a week. These symptoms subsided spontaneously after admission. No abnormality was found on physical examination or laboratory testing. Repeated estimations of plasma and . . .