Structural and compositional difference in the neutral glycolipids between epithelial and non-epithelial tissue of the mouse small intestine.

Five major neutral glycolipids, GL-1-GL-5, were isolated from the mouse small intestine. Their structures and distribution were determined by permethylation analysis, sequential degradation with exoglycosidases and/or immunohistochemistry. The molar ratio of GL-1, GL-2, GL-3, GL-4 and Gl-5 in the whole small intestine was 1:0.04:0.03:0.42:0.02. The structures of GL-1 and GL-4 present in epithelial cells were reported previously to be glucosyl ceramide and asialo GM1, respectively (Umesaki, Y., Suzuki, A., Kasama, T., Tohyama, K., Mutai, M. and Yamakawa, T. (1981) J. Biochem. 90, 1731-1738). GL-5, also present in the epithelial cells, was fucosyl asialo GM1, and fucose was shown to be linked to terminal galactose of asialo GM1 in the manner of alpha(1-2) bond. GL-2 and GL-3, present in the residual tissue after scraping the mucosa, were determined to be globoside and Forssman glycolipid, respectively. Both globoside and Forssman glycolipid of the non-epithelial tissue had non-hydroxy fatty acid (C16-C24) in combination with sphingosine (C18) as the ceramide components, in contrast with the ceramide structures of the epithelial glycolipids, which contained alpha-hydroxy fatty acids in combination with phytosphingosine. Immunohistochemical staining using anti-glycolipid antibodies confirmed the distribution of asialo GM1 and fucosyl asialo GM1, and Forssman glycolipid in the epithelial and non-epithelial tissue, respectively.