| First Author | Miyata M | Year | 2009 |
| Journal | Drug Metab Dispos | Volume | 37 |
| Issue | 2 | Pages | 338-44 |
| PubMed ID | 18988759 | Mgi Jnum | J:163803 |
| Mgi Id | MGI:4829760 | Doi | 10.1124/dmd.108.022590 |
| Citation | Miyata M, et al. (2009) Cholesterol feeding prevents hepatic accumulation of bile acids in cholic acid-fed farnesoid X receptor (FXR)-null mice: FXR-independent suppression of intestinal bile acid absorption. Drug Metab Dispos 37(2):338-44 |
| abstractText | Cholic acid (CA) feeding of farnesoid X receptor (Fxr)-null mice results in markedly elevated hepatic bile acid levels and liver injury. In contrast, Fxr-null mice fed cholesterol plus CA (CA+Chol) do not exhibit liver injury, and hepatic bile acid levels and bile acid pool size are reduced 51 and 40%, respectively, compared with CA-treated Fxr-null mice. These decreases were not observed in wild-type mice. Despite a reduced bile acid pool size, hepatic Cyp7a1 mRNA expression was increased in Fxr-null mice fed the CA+Chol diet, and biliary bile acid output was not changed. Analysis of other potential protective mechanisms revealed significant decreases in portal blood bile acid concentrations and a reduced ileal bile acid absorption capacity, as estimated using an in situ loop method. Fecal bile acid excretion was also increased in Fxr-null mice fed the CA+Chol versus CA diet. The decreased ileal bile acid absorption correlated with decreased ileal apical sodium-dependent bile salt transporter (ASBT) protein expression in brush-border membranes. These results suggest a critical role for ileal bile acid absorption in regulation of hepatic bile acid levels in Fxr-null mice fed CA+Chol. Furthermore, experiments with Fxr-null mice suggest that cholesterol feeding can down-regulate ASBT expression through a pathway independent of FXR. |
