Intestinal Absorption of Macromolecules and Epithelial Cell Surface Glycosylation in Suckling Rats Nursed on Mothers Fed Low-Protein Diet-I

Abstract

The effect of feeding 8 % protein (low-protein; LP) diet to lactating rats has been studied on the absorption of macromolecules and the glycosylation of enterocytes in suckling animals. The absorption of ¹²⁵I-labelled bovine serum albumin, γ-globulin and α-lactalbumin was 24–314% more in pups nursed on mothers fed LP diet compared to the pair-fed controls. The observed enhancement in protein absorption was associated with a significant increase in the binding of these proteins to microvillus membranes (MVM). The sialic acid content of brush borders was unaltered but the fucose level was augmented (p < 0.01) in pups nursed on rats fed LP diet. The binding of ¹²⁵I-labelled wheat germ agglutinin and Ulex europeus agglutinin I to MVM was in agreement to the data on sialic acid and fucose levels of the membranes. The binding of peanut agglutinin to MVM was 30% low in pups from LP-diet-fed animals. The incorporation of (¹⁴C) D-mannose into MVM was essentially unaffected but that of (¹⁴C) N-acetylglucosamine was reduced in pups reared on mothers given LP diet. These findings suggest that the quality of maternal nutrition affects the absorption of macromolecules and the glycosylation in developing rat intestine.

Effect of Chronic Ethanol Administration on Intestinal Microvillus Membrane Glycosylation in Rats Fed Rat Pellet Diet and Protein-Rich Diet.

“…Since surface oligosaccharides are well known to act as receptors ETHANOL AND MICROVILLUS MEMBRANE GLYCOSYLATION 141 for toxins and to participate in the adhesion of microorganisms in the intestinal lumen [3], it is likely that changes in MVM glycosylation could influence the quantity and quality of microflora in the intestine. Receptor-mediated endocytosis may also be affected under such dietary regimens [31].…”

Interrogation of Milk-Driven Changes to the Proteome of Intestinal Epithelial Cells by Integrated Proteomics and Glycomics

“…High-fat diets induce an increase in the sialo/sulfomucins ratio of colonic mucins in mice . In other studies, both fat and protein levels in the human diet have been shown to modulate intestinal glycosylation. , Restriction of dietary threonine significantly inhibits synthesis of intestinal mucins while vitamin A supplementation impacts the expression of numerous extracellular matrix proteins (ECM) including laminin, collagen, elastin, fibronectin, and proteoglycans . A deficiency in vitamin A is detrimental to the intestinal barrier reducing levels of MUC2 and defensin-6 expression, while also enhancing MUC3, TLR2, and TLR5 expression …”