Dietary spermidine and spermine participate in the maturation of galactosyltransferase activity and glycoprotein galactosylation in rat small intestine.

This study considered the role of dietary polyamines in the maturation of intestinal glycoprotein galactosylation during postnatal development. In the rat small intestine, O-glycan: beta-1,3-galactosyltransferase and N-glycan: beta-1,4-galactosyltransferase are, respectively, involved in the glycan chain biosynthesis of mucins and of glycoproteins in the brush border membranes. Their activities increase significantly at weaning, in parallel with a rise in the intestinal content of spermidine and spermine (as determined by high performance liquid chromatography) and in proportion to the polyamine increase in food intake. The oral ingestion of spermidine or spermine (at 0.4 micromol/g body) by immature suckling rats for 4 d reproduced the levels of spermine and spermidine in their intestines at the time of weaning and induced precocious and significant rises in O-glycan: and N-glycan: galactosyltransferase activities to those normally found after weaning. In parallel, more galactose residues (detected in the complex oligosaccharide chains of glycoproteins by specific lectins after electrophoresis and transfer to nitrocellulose membranes) were observed in the brush border membranes of spermidine- and spermine-treated rats. In contrast, the ingestion of putrescine or ornithine had no effect. Diets with different levels of polyamines (milks and commercial diet), when given at weaning, induced variable evolutions of the galactosylation process, partly in relation to the amounts of polyamines ingested. These results indicate that spermidine and spermine are maturation factors that can reproduce, in immature rats, the same increase in intestinal glycoprotein galactosylation that is normally observed during weaning. They also suggest that the maturation of glycoprotein galactosylation may be a multifactorial event in which spermidine and spermine are both involved.