Plasma atrial natriuretic factor and catecholamines before and during excision of pheochromocytoma.
We studied changes of atrial natriuretic factor (ANF) and catecholamines in three patients with pheochromocytoma occurring in the familial syndrome of multiple endocrine neoplasia type IIa. Previous studies have suggested a stimulating effect of catecholamines on ANF release. In pheochromocytoma, we observed normal basal ANF levels despite increased catecholamine secretion. In contrast, a rise in plasma ANF was observed when a hypertensive paroxysm occurred. Also during surgery, dissection of pheochromocytoma led to a rise in plasma ANF and catecholamines associated with an increase in blood pressure (in the 3 cases) and in pulmonary artery pressure (in 2 cases). We concluded that chronic elevation of basal catecholamines are without effect on plasma ANF but that manipulation of pheochromocytoma leads to a stimulation of ANF release, possibly mediated by either a direct effect of endogenously released catecholamines and/or an increase in atrial pressure.