Effect of Malnutrition and Hormone Treatments on Intestinal Microvillus Membrane Glycosylation in Suckling Rats

Abstract

Imposition of undernutrition in suckling rats significantly enhanced (p less than 0.001) sialic acid and reduced (p less than 0.001) fucose contents of intestinal microvillus membranes (MVM) compared to the controls. Administration of cortisone or insulin to undernourished (UN) pups reversed the sialylation and fucosylation pattern of the membranes. The binding of wheat germ agglutinin (WGA) to membranes was increased (p less than 0.001) and that of Ulex europeus agglutinin (UEA) was decreased in nutritionally deprived pups. Cortisone and insulin treatments reduced WGA and enhanced UEA bindings to UN membranes. The binding of peanut agglutinin (PNA) to UN membranes was 60% higher compared to that in the control rats. Cortisone and insulin treatments further enhanced PNA binding to the brush borders in UN pups. The incorporation of 14C-GlcNAc, 14C-mannose and 3H-fucose into MVM was reduced by 32-57% in UN suckling rats compared to the controls. The incorporation of labelled sugars into membranes from 21- and 50- to 60-day-old rats was essentially similar. Cortisone administration to UN pups augmented the incorporation of labelled GlcNAc and mannose but had no effect on fucose incorporation. Insulin treatment of UN pups insignificantly elevated GlcNAc incorporation into the membranes. These findings suggest that imposition of UN during early suckling period delays the maturational development of intestinal glycosylation. Cortisone and insulin induced adult-type glycosylation pattern of the brush borders in nutritionally deprived pups.