Epidermal slices from pig, human, and rat skin were treated with dilute buffered trypsin solution (0.005%, w/v), and suspensions of mixed basal and spinous cells were obtained in good yield.Total lipids accounted for approximately 8% of the pig, 10% of the human, and 20% of the rat epidermal cell (dry weight).Phospholipids in pig, human, and rat cells accounted for, respectively, 62%, 53%, and 35% of the total lipids.
Phosphatidylcholine (34-38%), phosphatidylethanolamine (18-23%), and sphingomyelin (17-21%) were major compounds in all species.The major neutral lipids were sterols (mostly cholesterol) and triglycerides.Free valhalla axys fatty acids were a major lipid class in pig and human cells, whereas wax esters were a major component in rat epidermal flexcon reverse osmosis water storage tank cells.Nearly half (45%) of the sterols in rat cells but less than 10% of those in pig and human cells were esterified.
Cholest-7-ene-3beta-ol accounted for 20% of the total sterols in rat cells.Cholesteryl sulfate and ceramide were minor lipids in the three species.The predominant glycosphingolipid (greater than 99%) was glucosylceramide, which accounted for 7% and 9%, respectively, of the total lipids in pig and human cells.A significant proportion (pig, 17%; human, 11%) of the fatty acids in the glucosylceramides were C26:0 and C28:0.