SIRT1 and Ureteral obstruction: Consistent with the results of the cell culture study, losartan reduced the renal tubular expression of GRP78 and increased the expression of SIRT1, HO-1, and thioredoxin in a mouse model of tunicamycin-induced ER stress and unilateral ureteral obstruction (UUO), which were abolished by pretreatment with sirtinol (SIRT1 inhibitor).