Barretts-esophagus - Over And Under-diagnosis
Gastroenterology & Hepatology
Fahmy N; King J; Doyle M
Gastroenterology
1995
1995-04
Journal Article or Conference Abstract Publication
n/a
Bile acids and FXR represses cholesterol 7A-hydroxylase (CYP7A1), sterol 12A-hydroxylase (CYP8B1) and sterol 27-hydroxylase (CYP27A1), but not oxysterol 7A-hydroxylase (CYP7B1) gene transcription
Gastroenterology & Hepatology
Chiang J Y; Chen W; Zheng M; Wu Z; Kimmel R; Stroup D
Gastroenterology
2000
2000-04
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1016/s0016-5085(00)86175-2" target="_blank" rel="noreferrer noopener">10.1016/s0016-5085(00)86175-2</a>
PEPTOCOCCUS-ASACCHAROLYTICUS BACTEREMIA WITH LIVER INVOLVEMENT CURED WITH ORAL METRONIDAZOLE
Gastroenterology & Hepatology
Watanakunakorn C
Gastroenterology
1982
1982
Journal Article
n/a
Alterations in cholesterol bile acid homeostasis following overexpression of cholesterol 7 alpha-hydroxylase (C7 alpha H) using a CMV-C7 alpha H adenoviral construct
Gastroenterology & Hepatology
Schwarz C; Mallonee D; Vlahcevic Z R; Hylemon P B; Lucas V; Chiang J Y L; Valerie K; Pandak W M
Gastroenterology
1996
1996-04
Journal Article
n/a
INTRADUODENAL (ID), BUT NOT INTRAVENOUS (IV) INFUSION OF TAUROCHOLATE (TCA) DOWN-REGULATES HMG-COA REDUCTASE (HMG-COA-R) AND CHOLESTEROL 7-ALPHA-HYDROXYLASE (C7-ALPHA-H)
Gastroenterology & Hepatology
Pandak W M; Vlahcevic Z R; Heuman D M; Chiang J Y L; Hylemon P B
Gastroenterology
1994
1994-04
Journal Article
n/a
HEP G2 CELLS - A MODEL FOR STUDIES OF HUMAN CHOLESTEROL 7-ALPHA-HYDROXYLASE (C7-ALPHA-H) AT THE MOLECULAR-LEVEL
Gastroenterology & Hepatology
Pandak W M; Stravitz R T; Chiang J Y L; Lucas V; Heuman D M; Hylemon P B; Vlahcevic Z R
Gastroenterology
1994
1994-04
Journal Article
n/a
EXPRESSION OF CHOLESTEROL 7-ALPHA-HYDROXYLASE IN RESPONSE TO CHOLESTEROL AND BILE-ACID FEEDING IN THE HAMSTER AND RAT
Gastroenterology & Hepatology
Pandak W M; Doerner M; Heuman D M; Hylemon P B; Chiang J Y L; Vlahcevic Z R
Gastroenterology
1995
1995-04
Journal Article
n/a
CYP7A1 is inhibited by activated FXR via SHP and LRH-1 in cholesterol-fed rabbits
Gastroenterology & Hepatology
Xu G R; Ananthanarayanan M; Forman B M; Li X G; Shefer S; Erickson S; Chiang J Y L; Tint G S; Salen G
Gastroenterology
2001
2001-04
Journal Article
<a href="http://doi.org/10.1016/s0016-5085(01)80063-9" target="_blank" rel="noreferrer noopener">10.1016/s0016-5085(01)80063-9</a>
FAILURE OF INTRAVENOUS-INFUSION OF TAUROCHOLATE TO DOWN-REGULATE CHOLESTEROL 7-ALPHA-HYDROXYLASE IN RATS WITH BILIARY FISTULAS
3-hydroxy-3-methylglutaryl; bile-acid synthesis; cholesterol; coenzyme; coenzyme-a reductase; feedback-regulation; Gastroenterology & Hepatology; hepatic; hepatocytes; liquid-chromatography; liver; messenger-rna levels; performance; transcriptional regulation
Background/Aims: The decrease in cholesterol 7 alpha-hydroxylase induced by intraduodenal infusion of taurocholate in bile fistula vats may be indirect, i.e., mediated through release or absorption of an intestinal factor in response to the presence of bile salts in the intestine. The aim of this study was to determine if negative feedback regulation of cholesterol 7 alpha-hydroxylase can be shown when equimolar concentrations of taurocholate are administered intravenously, thus bypassing the intestine. Methods: After 96 hours of biliary diversion, taurocholate (36 mu mol.h(-1).100 g rat(-1)) was infused into the rats either intravenously or intraduodenally for the final 24 hours. Livers were then harvested for analysis of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase specific activity, cholesterol 7 alpha-hydroxylase specific activity, messenger RNA levels, and transcriptional activity. Results: Intra-duodenally administered taurocholate significantly decreased HMG-CoA reductase and cholesterol 7 alpha-hydroxyfase specific activity by more than 50% and cholesterol 7 alpha-hydroxylase steady-state messenger RNA levels and transcriptional activity by 50%-75%. In contrast, intravenous administration of taurocholate failed to down-regulate either cholesterol 7 alpha-hydroxylase or HMG-CoA reductase. Conclusions: Passage of taurocholate through the intestine strongly potentiates negative feedback regulation of cholesterol 7 alpha-hydroxylase. A putative intestinal factor, released or absorbed in the presence of bile acids in the intestinal lumen, may play a role in the regulation of bile acid synthesis.
Pandak W M; Heuman D M; Hylemon P B; Chiang J Y L; Vlahcevic Z R
Gastroenterology
1995
1995-02
Journal Article
<a href="http://doi.org/10.1016/0016-5085(95)90083-7" target="_blank" rel="noreferrer noopener">10.1016/0016-5085(95)90083-7</a>
A novel role of transforming growth factor beta1 in transcriptional repression of human cholesterol 7alpha-hydroxylase gene.
Bile Acids and Salts/metabolism; Carcinoma; Cell Line; Cells; Cholesterol 7-alpha-Hydroxylase/*genetics/*metabolism; Cultured; Enzyme Inhibitors/pharmacology; Genetic/drug effects/*physiology; Hepatocellular/*metabolism/pathology; Hepatocyte Nuclear Factor 4/metabolism; Hepatocytes/drug effects/*metabolism/pathology; Humans; Hydroxamic Acids/pharmacology; Liver Neoplasms/*metabolism/pathology; Messenger/metabolism; RNA; Signal Transduction/physiology; Smad3 Protein/metabolism; Transcription; Transforming Growth Factor beta1/*metabolism; Tumor
BACKGROUND & AIMS: Inhibition of cholesterol 7alpha-hydroxylase (CYP7A1) by bile acids and inflammatory cytokines provides an important mechanism to protect hepatocytes from bile acid toxicity during cholestasis. Transforming growth factor beta1 (TGFbeta1) released by hepatic stellate cells during chronic liver injury plays a critical role in liver inflammation and fibrogenesis. The objective of this study is to investigate the role of TGFbeta1 in hepatic bile acid synthesis. METHODS: mRNA expressions in primary human hepatocytes and HepG2 cells were measured by quantitative real-time polymerase chain reaction. Reporter assay, glutathione-S-transferase pull-down assay, adenovirus-mediated gene transduction, and chromatin immunoprecipitation assay were used to study the mechanism of TGFbeta1 regulation of CYP7A1 gene transcription. RESULTS: TGFbeta1 inhibited the mRNA expression of CYP7A1 and bile acid synthesis in HepG2 cells and primary human hepatocytes. Mothers against decapentaplegic homolog (Smad3) inhibited both CYP7A1 promoter activity and mRNA expression by inhibiting
Li Tiangang; Chiang John Y L
Gastroenterology
2007
2007-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1053/j.gastro.2007.08.042" target="_blank" rel="noreferrer noopener">10.1053/j.gastro.2007.08.042</a>