| First Author | Rao A | Year | 2008 |
| Journal | Proc Natl Acad Sci U S A | Volume | 105 |
| Issue | 10 | Pages | 3891-6 |
| PubMed ID | 18292224 | Mgi Jnum | J:132778 |
| Mgi Id | MGI:3776946 | Doi | 10.1073/pnas.0712328105 |
| Citation | Rao A, et al. (2008) The organic solute transporter alpha-beta, Ostalpha-Ostbeta, is essential for intestinal bile acid transport and homeostasis. Proc Natl Acad Sci U S A 105(10):3891-6 |
| abstractText | The apical sodium-dependent bile acid transporter (Asbt) is responsible for transport across the intestinal brush border membrane; however, the carrier(s) responsible for basolateral bile acid export into the portal circulation remains to be determined. Although the heteromeric organic solute transporter Ostalpha-Ostbeta exhibits many properties predicted for a candidate intestinal basolateral bile acid transporter, the in vivo functions of Ostalpha-Ostbeta have not been investigated. To determine the role of Ostalpha-Ostbeta in intestinal bile acid absorption, the Ostalpha gene was disrupted by homologous recombination in mice. Ostalpha(-/-) mice were physically indistinguishable from wild-type mice. In everted gut sac experiments, transileal transport of taurocholate was reduced by >80% in Ostalpha(-/-) vs. wild-type mice; the residual taurocholate transport was further reduced to near-background levels in gut sacs prepared from Ostalpha(-/-)Mrp3(-/-) mice. The bile acid pool size was significantly reduced (>65%) in Ostalpha(-/-) mice, but fecal bile acid excretion was not elevated. The decreased pool size in Ostalpha(-/-) mice resulted from reduced hepatic Cyp7a1 expression that was inversely correlated with ileal expression of fibroblast growth factor 15 (FGF15). These data indicate that Ostalpha-Ostbeta is essential for intestinal bile acid transport in mice. Unlike a block in intestinal apical bile acid uptake, genetic ablation of basolateral bile acid export disrupts the classical homeostatic control of hepatic bile acid biosynthesis. |
