BILE SALT-ENHANCED RAT JEJUNAL-ABSORPTION OF A MACROMOLECULAR TRACER

  • 1 January 1981
    • journal article
    • research article
    • Vol. 44  (1) , 18-26
Abstract
Bile salt deconjugation may occur in the jejunum under conditions of fecal colonic overgrowth of the small intestine. The effects of conjugated and deconjugated bile salts on rat jejunal absorption of a macromolecular tracer, horseradish peroxidase [HRP], in an in vivo perfusion system, was studied. At a 0.5 mM perfusion concentration, only the deconjugated bile salts, cholate and deoxycholate, produced a significant increase in horseradish peroxidase absorption into serum. At a 0.5 mM concentration of the conjugated salt, taurocholate, horseradish peroxidase-absorption was indistinguishable from that seen in bile salt-free preparations. At a higher 5 mM concentration, the conjugated and deconjugated salts increased jejunal HRP absorption into serum over that seen in bile salt-free preparations; this absorption was most marked with the deconjugated salts. At a 0.5 mM level, the bile salts induced minimal Na and glucose transport alterations, but did not produce evidence of morphologic damage to villi or absorptive epithelial cell organelles. At a 5 mM level, the deconjugated salts induced glucose and Na transport abnormalities and appeared to damage cellular organelles. An alteration in the tight junctional barrier to macromolecular absorption may play a role in some of the enhanced HRP absorption seen with deoxycholic acid in these experiments. The process of an increased absorption of intact macromolecules induced by products of bacterial metabolism may be of pathologic significance in the etiology of immunologically-related intestinal disease or in toxigenic processes.