Table 3. Mass spectrometry analysis of ceramide in the biopsies from pigs after inhalation of deuterated d7-sphingosine. Levels of total deuterated d7-ceramide in the upper and lower half of the trachea, the lung and inner organs were very low compared to endogenous ceramide levels after inhalation of d7-sphingosine. We only detected deuterated d7-ceramide in the trachea, lung and liver, but not in heart, kidney and spleen. d7-C16-ceramide was the only detectable labeled ceramide species. Analyzed were 8 samples from the lung, i.e. each 2 samples per pig and each 3 samples for the trachea and liver. Samples were collected post mortem from the pigs 1 h after inhalation of d7 sphingosine. The levels of d7-ceramide were under the detection level in further 4 samples from lung, 5 samples from trachea, 1 sample from liver and in each 4 samples from kidney, heart and spleen. Those negative samples were not included in the calculation of the mean SD. Given is the mean SD of each parameter, *p < 0.05, **p < 0.01, ***p < 0.001, ANOVA