The phospholipid composition of plasma in various mammalian species.

Plasma phospholipids in several common mammalian species, including cat, cow, dog, goat, guinea pig, horse, pig, rabbit, rat, and sheep, were analyzed by using chromatographic and spectrophotometric methods. Lipids were extracted from plasma with chloroform-methanol 2ratio1 (v/v) and freed of nonlipid material by passage through a Sephadex column. The phospholipids were separated by two-dimensional thin-layer chromatography (TLC). Spots were identified by spray reagents, also by infrared spectrophotometry. The relative distribution of the phospholipids was determined by phosphorus analysis on the spot scraped off the TLC plate.Lecithin, lysolecithin, and sphingomyelin were found in the plasma of all species and accounted for more than 95% of the phospholipids except in the rodents. Lecithin was without exception the major phospholipid in plasma (56 to 83%). Lysolecithin and sphingomyelin content varied between 8 and 23% and 6 and 15% respectively. Phosphatidyl ethanolamine and phosphatidyl inositol were the only noncholine-containing phospholipids detected (detection limits 0.2%) in the plasma of these species. Together these compounds usually made up less than 5% of the total phospholipid. Rodents were an exception, especially the guinea pig, which had 21.7% phosphatidyl ethanolamine.