Distinct differences in lipid composition between epidermis and dermis from footpad and dorsal skin of guinea pigs.

All lipids, including neutral lipids, phospholipids and glycolipids, in the dermis and epidermis from footpad and dorsal skin of guinea pigs were quantitatively determined, and distinct and characteristic differences in lipid composition were observed in both regions. Ceramides, cerebrosides and cholesterol sulfate were abundant in the epidermis, the amounts being 8.8-12.0, 2.8-4.0 and 6.0-6.5 times higher than those in the dermis, respectively, whereas sulfatide was predominantly found in the dermis. Four and six bands of ceramides, and three and four bands of cerebrosides were detected for the lipids from both the epidermis and dermis on TLC, respectively, two of the ceramides and one of the cerebrosides being found to be esterified. Cerebrosides in the epidermis were predominantly glucocerebrosides, whereas those in the dermis comprised a mixture of gluco- and galactocerebrosides. In addition, an esterified cerebroside, glucosyl N-(O-linoleoyl-omega-hydroxylignoceroyl) sphingosine, was present in the epidermis as a tissue-characteristic compound and this finding seems to be common for several animal species. The marked differences in lipid components between the epidermis and dermis should be quite useful for discriminating these functionally as well as histologically different regions on a biochemical basis.