Studies on the lipids of sheep red blood cells. I. Lipid composition in low and high potassium red cells.

The lipid composition of whole red blood cells was investigated in five sheep with red cells containing a low concentration of potassium (LK) and in five sheep with red cells containing a high concentration of potassium (HK). No apparent differences within the limit of error of the experiment were detected in the lipid class composition between the HK and LK red cells. Cholesterol, the only nonpolar lipid detected in the tissue, was present in oneto-one molar ratio to the total phospholipids. Phosphatidyl ethanolamine and sphingomyelin accounted for 85% of the total phospholipids; phosphatidyl serine, phosphatidyl inositol, phosphatidic acid, and lysolecithin were present in lesser amounts. No lecithin was detected in any of the animals in this investigation. Plasmalogen compounds were found only in the ethanolamine lipids. The molar ratio of choline to noncholine phospholipids was also approximately one to one. It was concluded that the major lipid class distribution in the two types of red cells cannot be directly responsible for the differences observed in the cation concentrations in these cells in the two species of sheep.