Galactocerebroside and not glucocerebroside or ceramide stimulate epidermal β-glucocerebrosidase activity

Abstract Glycosphingolipids including glucocerebroside (GluCer) and galactocerebroside (GalCer) have been recognized as bioreguratory lipids by our group and others. In addition, our recent study demonstrated that GalCer corrects dry skin conditions in humans. The processing of stratum corneum lipids, which occurs when β-glucocerebrosidase (β-GluCer'ase) changes GluCer to ceramide (Cer), is required to form the epidermal permeability barrier. We herein investigated the effects of GluCer, GalCer and Cer on the processing of GluCer to Cer by assaying epidermal β-CluCer'ase in mice (155%, P P P P