The effects of ethanol administration on brush border membrane glycolipids in rat intestine

Ethanol ingestion is well known to induce morphological and biochemical changes in intestine and is responsible for intestinal dysfunctions. Luminal surface of enterocytes is rich in glycolipids, but the effects of ethanol ingestion on membrane glycolipids are not well characterized. In the present study, rats were given 1 mL of 30% ethanol daily for 15, 25, 35, and 56 days. Ethanol feeding for 15 days did not affect glycolipid pattern in microvillus membranes, but the levels of cerebrosides (glucosylceramide, lactosylceramide, globotriasyloceramide) were enhanced in rats fed with ethanol for 35 or 56 days compared with controls. In contrast, the content of fucolipids and gangliosides was reduced in rats on ethanol ingestion for 35 or 56 days. The observed changes in membrane glycolipids were substantiated using biotinylated lectins Jacalin (affinity for N-acetylgalactosamine) and Aleuria aurantia (affinity for α-l-fucose). The incorporation of [(14)C]-mannose and [(14)C]-glucosamine revealed an increase (P<.01) in glucosamination and reduction (P<.01) in mannosylation of glycolipids from ethanol-fed rats for 45 days compared with controls. These findings were further characterized by autoradiography of the glycolipids separated on thin layer chromatograms. These findings indicate that ethanol ingestion modulates the glycolipids composition of brush borders, resulting in generalized aberration of intestinal glycosylation in chronic alcoholism in rats.