Inhibition of both cystathionine-γ-lyase (CSE) and cystathionine-β-synthase (CBS), 2 major enzymes for endogenous H<sub>2</sub>S production, with propargylglycine (PPG) and amino-oxyacetate (AOAA), respectively, caused increased urine output and reduced urine osmolality in mice that was associated with decreased expression of aquaporin (AQP)-2 in the renal inner medulla.