Fig. 3. The pulmonary vasorelaxation to inhaled nitric oxide (NO) in lipopolysaccharide (LPS)- (closed circles) and saline-challenged (open circles) mice and in lipopolysaccharide-challenged mice treated concomitantly with 20 (closed squares) or 100 U/g (closed triangles) polyethylene glycol-catalase (PEG-cat) administered intraperitoneally. Vasorelaxation to inhaled NO was partially preserved in mice treated with lipopolysaccharide and 20 U/g PEG-cat (P < 0.05 vs. lipopolysaccharide alone). Responsiveness to inhaled NO was fully preserved after treatment with lipopolysaccharide and 100 U/g PEG-cat (P < 0.01 vs. lipopolysaccharide alone and vs. 20 U/g PEG-cat).