Lysophosphatidylcholines in rat plasma. (A.) Thin layer chromatography showing the lysoPC spot relative to other abundant plasma lipids. Abbreviations: Cer-ceramide; Galcer- galactoceramide; PC- phosphatidylcholine; PE- phosphatidylethanolamine; SM- sphingomyelin; PI- phosphatidylinositol. Chol- free cholesterol; FFA- free fatty acids; LysoPC- lysophosphatidylcholine. InCer- internal control. (B.) Standard curve prepared with a mixture of lysoPCs 16:0, 18:0, and 18:1 showing semi-quantitative nature of TLC method (see text). Total intensity of the lysoPC spots at different concentrations were normalized to the intensity of the internal control spot (Incer) developed on the same plate. (C.) Mol percent of individual species of lysoPCs in the samples calculated from mass spectra of plasma lipid extracts relative to total lysoPC present in the samples. Note that in rat, as described for human, lysoPCs 16:0 and 18:0 are the most abundant species found in plasma[16, 39]. Inset: Typical MS spectra from plasma lipid extract showing identified lysoPC species and internal standards (i.s.). m/z = mass/charge ratio.