Increased uptake and accumulation of catecholamines by red blood cells in phaeochromocytoma

Red blood cell (RBC) and plasma catecholamine content were determined by high performance liquid chromatography in 18 patients suspected of having phaeochromocytoma on the basis of clinical manifestations, especially hypertension and laboratory findings. Eight normotensive health individuals served as controls. The fivne patients with tumours had strikingly greater RBC catecholamine concentrations (C) than in plasma and reached CRBS/Cplasma ratios approximating 5, significantly different from the ratios in controls and in hypertensive patients without tumours. One tumour patient had a normal RBC catecholamine content as well as repeatedly normal plasma and urinary catecholamine levels. The other 12 patients, who had no ++tumours, had only slight elevations in plasma and RBC catecholamine levels. There is an accelerated uptake of catecholamines against a concentration gradient by the RBC in phaeochromocytoma, which indicates that RBC play a major role in the clearance of catecholamines after they are secreted into circulation.