Renin-angiotensin system unresponsiveness in phaeochromocytoma

Water immersion to the neck is able to provoke a profound suppression of the renin-angiotensin system in several clinical conditions associated with hyper-reninaemia. Both hyper-reninaemia and secondary aldosteronism have sometimes been described in phaeochromocytoma. We report on two patients, with surgically proven phaeochromocytoma, in whom water immersion, performed before surgery, failed to induce any significant change in plasma renin activity.