Oxidative and nitrosative stress in kidneys of mice exposed to acute hypoxia. (A) Renal 3-nitrotyrosine (3-NTyr) protein content in renal tissue. Renal NTyr was measured by HPLC with electrochemical detection and NTyr was expressed in nmol/g protein. Increases in protein nitrotyrosine were found in both groups of mice at 6 to 24 hours of hypoxia. Values are means ± SEM (n = 4 mice per group at each time point; *P < .05). (B) GSSG/GSH ratio as a percentage of total GSH. Significant stress on the thiol pool was detectable early in hypoxia in the KO but not in the Wt strain. Values are mean ± SEM (n = 4 animals per group at each time point; *P < .05).