Role of angiotensin II in the pathogenesis of hyperdipsia in chronic renal failure

The relation of thirst to the renin-angiotensin system was examined in 38 patients with chronic renal failure receiving hemodialysis treatment. They were classified into three groups, ie, group 1 (19 patients), no or modest thirst; group 2 (13 patients), moderate thirst; and group 3 (six patients), excessive thirst. The plasma renin activity, plasma angiotensin II levels, and interdialytic weight gains of groups 1 to 3 significantly increased in a progressive manner with intensity of thirst. The hyperdipsia experienced by four patients in group 3 ameliorated after administration of an angiotensin-converting-enzyme inhibitor. The hyperdipsia of some patients with chronic renal failure therefore appears to be mediated by increased production of endogenous angiotensin II.