Effects of orally administered spermidine on absorptive enzyme and nutrient transporter gene expression in the rat small intestine during postnatal development

The developmental profiles of mRNA and protein expression for ornithine decarboxylase (ODC), the Na$ sp+$-dependent glucose co-transporter (SGLT1), sucrase isomaltase (SI), and the Na$ rm sp+K sp+$ ATPase $ alpha sb1$ and $ beta sb1$ subunit isoforms in the postnatal rat small intestine, as well as the effects of exogenous spermidine on their precocious development, were examined. Postnatal age had a significant effect with all enzymes and the nutrient transporter maturing around weaning. Consecutive exposure to exogenous spermidine during suckling precociously induced ODC mRNA, SI protein, and SGLT1 gene expression in the proximal and distal small intestine. Levels of Na$ rm sp+K sp+$ ATPase $ alpha sb1$ and $ beta sb1$ subunit isoform mRNA were precociously induced in the proximal small intestine only. These findings show that exposure to exogenous spermidine can promote precocious alterations in intestinal enzyme and nutrient transporter expression; however, it appears that spermidine must be continuously supplied for these alterations to persist in suckling rats