The effects of bile acid feeding on the development of ileal bile acid transport.
Sodium-dependent bile acid uptake is developmentally regulated in the rat ileum. Transport activity is abruptly expressed on postnatal d 17, although the mechanisms controlling this expression are poorly understood. Changes in bile salt metabolism and hepatic transport result in a marked increase in bile flow before postnatal d 17, and thus this study examined the effects of bile salt feeding on the development of ileal bile acid transport. Twelve-d-old rat pups were gavage-fed saline, taurocholate, or mannitol on a daily basis for 3 d. Sodium-dependent bile acid transport was studied by rapid filtration using ileal brush-border membrane vesicles prepared from the various experimental groups. Taurocholate feeding resulted in precocious development of sodium-dependent bile acid transport and induction of sucrase activity. Mannitol feeding, used as a control for the effects of diarrhea-induced stress, resulted in similar sucrase activity, yet sodium-dependent bile acid transport was induced to only half the level observed in taurocholate-fed animals (3.2 +/- 1.6 versus 6.9 +/- 2.0 pmol/mg protein/45 s, p < 0.001). Serum corticosterone levels were similar in the mannitol- and taurocholate-fed animals (3.8 +/- 1.3 versus 4.6 +/- 1.8 micrograms/dL). Both feedings lead to histologic maturation of the ileum, with a more pronounced effect in the taurocholate-fed pups. Bile salt feeding induces precocious expression of ileal bile acid transport, apparently by both diarrhea-induced stress and a bile salt-specific effect.
Shneider
B L
BL
Department of Pediatrics, Yale University, New Haven, Connecticut 06510.
Michaud
G A
GA
West
A B
AB
Suchy
F J
FJ
D000367:Age Factors; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism* / Q000494:pharmacology*; D001693:Biological Transport, Active; D007082:Ileum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D008353:Mannitol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013656:Taurocholic Acid / Q000494:pharmacology
D001647:Bile Acids and Salts; D008353:Mannitol; D013656:Taurocholic Acid