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This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This endoplasmic reticulum membrane protein catalyzes the first reaction in the cholesterol catabolic pathway in the liver, which converts cholesterol to bile acids. This reaction is the rate limiting step and the major site of regulation of bile acid synthesis, which is the primary mechanism for the removal of cholesterol from the body. CYP7A1 is activated by PGC-1alpha. CYP7A1 polymorphism has a small but significant effect on the increase in plasma HDL cholesterol and plasma total cholesterol after an increased intake of dietary cholesterol and cafestol, respectively. CYP7A1 regulates the pathway through which cholesterol is converted into bile acids. Data reveal a fundamental difference in the regulation of CYP7A1 in rodent and human hepatocytes. Human CYP7A1 deficiency: progress and enigmas. Review. New metabolic disorder presenting with hyperlipidemia caused by a homozygous deletion mutation in CYP7A1. Present study indicates that a tight fit of cholesterol in the CYP7A1 active site is in part responsible for the high efficiency of cholesterol turnover by CYP7A1 in the liver. The liver receptor homolog-1 has emerged as an essential regulator for the expression of CYP7A1. This study has found that several kinase activators rapidly reduce the amount of bile acid produced by the human hepatoma cell line, HepG2, and that gpCYP7A1 from HepG2 cell extracts eluted in the phosphoprotein fraction of FeIII columns. Bile acids suppress transcription of the gene (CYP7A1) encoding cholesterol 7alpha-hydroxylase, the rate-limiting enzyme in bile acid biosynthesis. Characterization of the coordinated regulation of cholesterol metabolism in human liver; regulation of its mRNA in liver. Cytochrome P450, subfamily VIIA (cholesterol 7 alpha-monooxygenase), polypeptide 1. Data indicate that thyroid hormone can repress the human cholesterol 7 alpha-hydroxylase(CYP7A1) gene in transgenic mice, but this effect is dependent on gender. Data suggest that the lack of an LXR element in the region from -56 to -49 of the human CYP7A1 promoter may account for some of the differences in response to diets between humans and rodents. Demonstrated that FGF-19, acting as an FXR-induced signaling molecule, represses expression of the CYP7A1 gene; this signaling cascade defines a novel mechanism for feedback repression of bile acid biosynthesis. Dietary cholesterol regulates bile acid pool size, fecal bile acid excretion, and plasma cholesterol independently of Cyp7a1 activity. Regulation by HNF-4alpha. Regulation of CYP7A1 and CYP27A1 in human liver.
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