Increased circulating concentration of atrial natriuretic factor in persons with pheochromocytomas

To investigate the possible relationship of atrial natriuretic factor (ANF) to hypertension, we examined the circulating levels of ANF in 3 patients with pheochromocytomas before surgery, during increase of their blood pressure with surgical manipulation of their tumors, and after surgery when their blood pressures returned to normal. The circulating levels of ANF were increased 2-fold in patients with both extra-adrenal and intra-adrenal pheochromocytomas. In both the intra-adrenal and extra-adrenal patients their ANF levels increased further during surgical manipulation and returned to normal after surgical removal of their respective tumors. Each of these pheochromocytomas was examined and found to have atrial natriuretic receptors that were functional since ANF could enhance the guanylate cyclase - cyclic GMP system two-fold in these pheochromocytomas. We conclude that ANF circulates at higher concentrations in persons with pheochromocytomas and returns to normal with removal of the tumor. In addition, pheochromocytomas contain specific ANF receptors and ANF itself within these tumors.