Lipids of epidermis and keratinized and non-keratinized oral epithelia.

Lipid compositions have been determined by quantitative thin-layer chromatography for epidermis, floor of mouth, gingiva, palate and buccal epithelium of the pig (Sus scrofa). All of the epithelia contained phospholipids, glycosylceramides, cholesteryl sulfate, cholesteryl esters, free sterols, fatty acids and triglycerides. Epidermis, palate and gingiva had similar lipid compositions, which were characterized by the presence of O-acylglycosylceramides, O-acylceramides and relatively high proportions of ceramides. Floor of mouth and buccal epithelium, which are not keratinized, contained no O-acylglucosylceramides or O-acylceramides and very little ceramide. The higher water permeability of the non-keratinized oral regions may reflect the absence of acylglucosylceramides and the low proportions of ceramides.