Abstract
Effect of chronic ethanol administration daily for 40 days together with 30% protein (HP) diet on microvillus membrane (MVM) glycosylation in rat intestine was studied. Ethanol administration to rats on a normal diet enhanced the hexose and sialic acid contents of brush borders but significantly reduced (p<0.05) membrane fucose levels. Feeding of the HP diet induced a generalized increase in MVM glycosylation. Ethanol feeding of rats maintained on the HP diet differently affected membrane glycosylation. Hexosamine content was enhanced, fucose and hexose contents were reduced, and sialic acid levels were unaltered under these conditions. The binding of 125I-wheat-germ agglutinin and 125I-peanut agglutinin to MVM was compatible with the chemical analysis of sugars in the various experimental groups. Incorporation of [14C] mannose or [14C]glucosamine into MVM from different groups of rats revealed an increase in mannosylation but a decrease in glucosamine incorporation into MVM from ethanol- or HP-fed animals. Ethanol feeding along with HP diet enhanced the incorporation of labelled sugars into MVM compared with that of the HP-fed controls. Electrophoretic distribution of radiolabelled membrane glycoproteins from the different groups revealed that glycoproteins of Mr 60, 000 were highly labelled. These results suggest that ethanol ingestion along with control or HP diet markedly modifies the intestinal MVM glycosylation but that these effects vary under different dietary regimens.
