[The role of catecholamine content in human platelets; clinical implications in patients with pheochromocytoma]

This study examined if the platelet catecholamine content (CA) in healthy adults and patients with adrenal tumors reflected the activity of the sympatho-adrenomedullary system.

(1) In 44 healthy adults, platelet norepinephrine (NE) levels ranged from 72 to 1175 pg.mg-1.protein-1 (mean: 473pg.mg-1.protein-1) and platelet epinephrine (E) levels ranged from 23 to 273 pg.mg-1.protein-1 (mean: 68 pg.mg-1.protein-1). These were used as normal ranges for this study. (2) In patients with adrenal tumors, plasma CA level, urinary CA elimination and platelet CA content were higher in patients with pheochromocytoma than in those with other adrenal tumors. Mean platelet NE and E levels for patients with pheochromocytoma were 2188 and 336 pg.mg-1.protein-1, respectively. These results indicate that a large amount of CA is contained in platelets (particularly in patients with pheochromocytoma), and that platelet CA level is very useful for preoperative diagnosis of pheochromocytoma. The results also suggest that platelet CA level closely reflects the activity of the sympatho-adrenomedullary system.