DYNAMIC CHANGES IN THE CELLULAR-DISTRIBUTION OF FREE AND SULFOCONJUGATED CATECHOLAMINES IN THE PERIOPERATIVE STATE OF SURGERY FOR PHEOCHROMOCYTOMA

Concentrations of free and sulfated norepinephrine and epinephrine in plasma, platelets and red blood cells from four patients with pheochro mocytoma and twelve healthy volunteers were determined using a radio-e nzymatic method with a HPLC separation technique. All patients had mar kedly elevated concentrations of catecholamines in their plasma, plate lets and red blood cells. Regarding the relative proportions of free a nd total norepinephrine and epinephrine in these samples, no differenc es between the patients and the control persons were found. Tumor mani pulation during surgery was associated with a 2.8 to 14 fold increase in plasma concentrations of free norepinephrine and epinephrine. This sudden intraoperative release led to 2.6 to 3.2 fold increments in cat echolamine contents of platelets and red blood cells, respectively, wh ich reached their maxima with a delay of 5 to 15 minutes as compared t o the corresponding peak levels in plasma. In all three compartements, the concentrations of sulfated catecholamines showed a slower and a l ess distinct increase than those of the unconjugated compounds. After tumor resection, the concentrations of free norepinephrine and epineph rine in plasma and red blood cells decreased dramatically whereas the corresponding values in platelets diminished at a slower rate. These d ata suggest that the cellular accumulation of catecholamines is probab ly not very efficient as buffering mechanism to adverse hemodynamic co nsequences of sudden release of free catecholamines, since it is slowe r than the initial increase in the concentrations of these hormones in plasma.