NOS isoform protein levels in the mouse lung after LPS exposure. Protein levels for eNOS, nNOS, and iNOS were determined in lung tissues 2- and 4-h after LPS exposure by Western blot analysis using specific antisera raised against eNOS, nNOS, or iNOS respectively and re-probed with β-actin to normalize for loading. Representative Western blots are shown for eNOS (panel A), nNOS (panel B), and iNOS (panel C). There are no changes in eNOS or nNOS protein levels but iNOS protein levels are significantly increased 4 h after LPS exposure. Values are mean ± SE, N=5 for each group *P<0.05 compared to no LPS.