Studies of the renal effects of angiotensin II receptor blockade: The confounding factor of acute water loading on the action of vasoactive systems

摘要: . The acute renal tubular effects of two pharmacologically distinct angiotensin II receptor antagonists have been evaluated in normotensive volunteers on various salt diets. In the first study, response to a single oral dose losartan (100 mg) was assessed subjects low (50 mmol Na/d) and high (200 intake. second protocol, 50 mg irbesartan were investigated receiving 100 Na/d diet. Both induced significant increase urinary sodium excretion. With losartan, modest, transient potassium uric acid excretion found. contrast, no change excretions observed with irbesartan, suggesting that are due intrinsic pharmacologic properties rather than specific blockade receptors. Assessment segmental reabsorption using lithium as marker proximal demonstrated decreased distal both antagonists. A direct natriuretic effect antagonist could be only irbesartan. This apparent discrepancy allowed us reveal importance water loading possible confounding factor studies. results present analysis show per se may enhance hence modify level activity renin-angiotensin system expected from given Since is common practice clinical studies, this should taken into account when investigating vasoactive systems.