Fig. 7.
Lung ceramide levels in response to cigarette smoke exposure in mice. A: levels of endogenous ceramides measured by tandem mass spectrometry and normalized by lipid phosphorus in lungs of mice exposed to air (n = 5) or cigarette smoke (Csk; n = 5) for 4 wk (means ± SE; *P = 0.01). B: levels of endogenous dihydroceramides, immediate precursors of ceramides in the de novo synthetic pathway, measured by tandem mass spectrometry and normalized by lipid phosphorus in the lungs of mice exposed to air or Csk for 4 wk (means ± SE; *P = 0.003).