Formation of RBC S-nitrosothiols in iNOS^–/– mice and a surgical model of sepsis. (A) RBC nitrate and nitrite in WT or iNOS^–/– mice treated with saline or LPS. (B) Corresponding RBC S-nitrosothiol concentrations. (C-D) Changes in RBC nitrate, nitrite, and S-nitrosothiols measured at 5 or 20 hours (▦ and ▪, respectively) after cecal ligation and puncture. ▧ represents control RBCs. Data represent mean ± SEM (n = 3-5). *P ≤ .05 versus control.