Nitrite protection against TNF-induced hypothermia and mortality. Results for protection against hypothermia (left) and mortality (right) are shown. (A and B) WT mice were injected i.v. with 6 µg TNF at t = 0 and were pretreated i.v. with PBS or 0.1, 0.2, 0.3, 0.7, or 1.3 mg/kg sodium nitrite 2 h earlier (n = 5 for each group, except for 0.7 mg/kg [n = 4]). (C and D) WT mice were injected i.v. with 8 µg TNF at t = 0 and were pretreated i.v. with PBS or 0.2 or 1.3 mg/kg sodium nitrite 2 h earlier (n = 5). (E and F) WT mice were injected i.v. with 6 µg TNF at t = 0 and were treated i.v. with PBS (n = 12) or 1.3 mg/kg sodium nitrite 3 h later (arrow). The combined results of two independently performed experiments are shown (n = 14). (G and H) WT mice were injected i.v. with 7 µg TNF. Control TNF-treated mice received normal drinking water, and the other groups received 1 wk of 500 mg/liter of nitrite drink. In addition, mice were injected with 1 mg/kg nitrite at −2 or +4 h (n = 6 for all groups; a representative experiment is shown, repeated twice). Data are means ± SEM. **, P < 0.01; and *, P < 0.05 compared with control TNF-challenged animals.