Cholesterol and bile acids regulate cholesterol 7 alpha-hydroxylase expression at the transcriptional level in culture and in transgenic mice.

Transgenic Mice. Transcriptional Level in Culture and in 7 Alpha-hydroxylase Expression at the Cholesterol and Bile Acids Regulate Cholesterol

Differential feedback regulation of cholesterol 7 alpha-hydroxylase mRNA and transcriptional activity by rat bile acids in primary monolayer cultures of rat hepatocytes.

We have used primary monolayer cultures of rat hepatocytes to study the effects of physiological concentrations of various bile acids, commonly found in bile of normal rats, on the mechanism of regulation of cholesterol 7 alpha-hydroxylase and bile acid synthesis. Addition of taurocholic acid, the most predominant bile acid in rat bile, to the culture medium suppressed cholesterol 7 alpha-hydro...

Transgenic Expression of Cholesterol-7- -Hydroxylase Prevents Atherosclerosis in C57BL/6J Mice

C57BL/6J mice are susceptible to atherosclerosis when fed a diet consisting of fat, cholesterol, and taurocholate. The susceptibility to diet-induced atherosclerosis is linked to a reduction in plasma high density lipoprotein (HDL). Diet-induced reduction of plasma HDL shows a physiological and a genetic correlation with repression of cholesterol-7-hydroxylase, the liver-specific enzyme that re...

Absence of negative feedback control of bile acid biosynthesis in cultured rat hepatocytes.

The effect of individual bile acids on bile acid synthesis was studied in primary hepatocyte cultures. Relative rates of bile acid synthesis were measured as the conversion of lipoprotein [4-14C]cholesterol into 4-14C-labeled bile acids. Additions to the culture media of cholate, taurocholate, glycocholate, chenodeoxycholate, taurochenodeoxycholate, glycochenodeoxycholate, deoxycholate, and tau...

Activation of LXRs prevents bile acid toxicity and cholestasis in female mice.

UNLABELLED Liver X receptors (LXRs) have been identified as sterol sensors that regulate cholesterol and lipid homeostasis and macrophage functions. In this study, we found that LXRs also affect sensitivity to bile acid toxicity and cholestasis. Activation of LXRalpha in transgenic mice confers a female-specific resistance to lithocholic acid (LCA)-induced hepatotoxicity and bile duct ligation ...