Free sphingosines in oral epithelium

Free sphinogosines, intermediates in the biosynthesis of ceramides and inhibitors of protein kinase C, have been found to be present in significant concentrations in epidermis and oral epithelia of the pig (Sus scrofa). Concentrations of sphingosines were higher in the outer portion of epidermis (4.4 mg/g), palatal epithelium (3.9 mg/g) and buccal epithelium (0.7 mg/g) compared to the inner portion of the epithelia (1.0, 0.9 and 0.4 mg/g, respectively). Free sphingosines may provide antimicrobial activity at the epithelial surfaces, and the sphingosine gradient may modulate epithelial differentiation.