Publications by authors named "Z Rano Vlahcevic"
Article Synopsis
- Cholesterol is primarily broken down into bile acids through two main pathways: the classic pathway involving CYP7A1 and an alternative pathway using CYP27 and CYP7B1.
- The study aimed to investigate how bile acids, cholesterol, and thyroid hormones regulate CYP7B1 compared to CYP7A1 in different groups of Sprague-Dawley rats.
- Results showed that complete biliary diversion significantly increased both CYP7B1 and CYP7A1 activity, while the introduction of bile acids or cholesterol in the diet downregulated their activities.
Conversion of cholesterol into 7alpha-hydroxylated bile acids is a principal pathway of cholesterol disposal. Cholesterol 7alpha-hydroxylase (CYP7A1) is the initial and rate-determining enzyme in the "classic" pathway of bile acid synthesis. An "alternative" pathway of bile acid synthesis is initiated by sterol 27-hydroxylase (CYP27) with subsequent 7alpha-hydroxylation of 27-hydroxycholesterol by oxysterol 7alpha-hydroxylase (CYP7B1).
View Article and Find Full Text PDFEffects of CYP7A1 overexpression on cholesterol and bile acid homeostasis.
Am J Physiol Gastrointest Liver Physiol
October 2001
Article Synopsis
- The study investigates the impact of overexpressing cholesterol 7alpha-hydroxylase (CYP7A1) on cholesterol regulation in human liver cells.
- Using recombinant adenovirus, researchers found that increased CYP7A1 activity significantly boosted bile acid biosynthesis while simultaneously lowering HMG-CoA-reductase (HMGR) and acyl CoA:cholesterol acyltransferase (ACAT) activities.
- Findings indicate that this overexpression also enhanced low-density lipoprotein receptor (LDLR) expression and altered enzyme activities, suggesting a complex relationship between cholesterol degradation and synthesis in human liver cells.
Overexpression of CYP27 in hepatic and extrahepatic cells: role in the regulation of cholesterol homeostasis.
Am J Physiol Gastrointest Liver Physiol
July 2001
In the liver, sterol 27-hydroxylase (CYP27) participates in the classic and alternative pathways of bile acid biosynthesis from cholesterol (Chol). In extrahepatic tissues, CYP27 converts intracellular Chol to 27-hydroxycholesterol (27OH-Chol), which may regulate the activity of 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoA-R). This study attempts to better define the role of CYP27 in the maintenance of Chol homeostasis in hepatic and extrahepatic cells by overexpressing CYP27 in Hep G2 cells and Chinese hamster ovary (CHO) cells through infection with a replication-defective recombinant adenovirus encoding for CMV-CYP27.
View Article and Find Full Text PDFBackground & Aims: The rate of 12alpha-hydroxylation of bile acid intermediates is believed to determine the ratio of cholic acid (CA) to chenodeoxycholic acid (CDCA) biosynthesis and the overall hydrophobicity of the bile acid pool. The aim of this study was to determine the effects of the level of expression of sterol 12alpha-hydroxylase (CYP8b1) and cholesterol 7alpha-hydroxylase (CYP7a1) on rates of CA biosynthesis and bile acid pool composition.
Methods: Expression of CYP8b1 and CYP7a1 was accomplished through infection of primary rat hepatocytes (PRH) or intact male SD rats with replication-defective recombinant adenoviruses encoding either CYP8b1 or CYP7a1.