Influence of the Polyamine, Spermidine, on Intestinal Maturation and Dietary Antigen Uptake in the Neonatal Rat

Abstract

SummaryPolyamines appear to have an important role in postnatal growth of the rat intestine. In the present study, we examined the effect of spermidine on the maturation of the intestine and on its ability to exclude macromolecules. Two litters of Sprague‐Dawley rat pups were assigned to one of four experimental groups. These groups received, on Days 7, 8, and 9, either (a) saline by gavage; (b) spermidine, 0.9 mg (6 μmol) by gavage; (c) cortisone acetate, 3.5 mg i.p.; or (d) saline i.p. On Day 10, animals were fed by gavage with a mixture of bovine serum albumin (BSA; 2 mg/g) and the γ‐globulin fraction of mouse antiovalbumin (anti‐OVA) antiserum (1 mg/g) and were bled 4 h later. Intestinal tissues were processed for histologic examination, sucrase determination, and identification of neonatal intestinal Fc receptor (FcRn) by Western blot. Serum immunoreactive BSA (iBSA) and mouse IgG1 and IgG2a anti‐OVA antibodies were estimated by enzyme‐linked immunosorbent assay. Sucrase activity was elevated in cortisone‐ and spermidine‐treated compared to control rats. iBSA and anti‐OVA were significantly reduced in cortisone‐treated compared to control rats but were not diminished significantly in the spermidine‐treated animals. A decrease in the neonatal intestinal Fc receptor was apparent in the spermidine‐fed group; cortisone produced a large reduction in FcRn. Spermidine‐fed animals showed morphologic evidence of maturation, with loss of giant vacuoles in the distal intestine; cortisone did not produce significant changes in morphology. Thus, while spermidine, like cortisone, enhanced the appearance of the disaccharidase sucrase, it did not significantly reduce the uptake of BSA or IgG, which is usually observed in mature compared to immature animals. The reason for this dichotomy is not known.