Renal carbonic anhydrases are involved in the reabsorption of endogenous nitrite

► Acetazolamide intake by healthy subjects increases urinary nitrite excretion. ► Renal carbonic anhydrases are involved in nitrite reabsorption. ► Nitrite reacts with carbon dioxide. ► Carbonic anhydrases may potentially catalyze this reaction. ► Renal carbonic anhydrases may modulate NO homeostasis in the circulation.