Evidence for the physiological occurrence of lysolecithin in rat plasma*

Abstract

An improved separation of phospholipids on activated silicic-acid columns was achieved by stepwise elution with increasing concentrations of methanol in chloroform. Chemical analyses and paper strip chromatography demonstrated that the noncholine-containing fraction was free of choline-containing phospholipids, and that the lecithin and lysolecithin were of high purity. Rat plasma was shown to contain on the average 17.5% of its lipid phosphorus in the form of lysolecithin. The following is evidence that plasma lysolecithin is not an in vitro breakdown product: (a) rapid glass-paper chromatography of lipid extracts showed the presence of a distinct spot with the Rf of lysolecithin, (b) after P32 injection the specific activity of lysolecithin was less than that of lecithin, (c) silicic-acid chromatography of C14-labeled plasma lipids failed to show a significant liberation of fatty acids, and (d) rechromatography of P32-labeled lecithin did not give rise to a lysolecithin peak.