Cholesterol 7 alpha hydroxylase. Medical search. Frequent questions

To investigate the biochemical background of these changes, the effects of insulin on bile acid synthesis and cholesterol 7 alpha-hydroxylase and sterol 27-hydroxylase, two key enzymes in routing of cholesterol toward bile acids, were studied in cultured rat hepatocytes. (eurekamag.com)
The decrease of bile acid synthesis correlated well with the suppression of cholesterol 7 alpha-hydroxylase and sterol 27-hydroxylase activity. (eurekamag.com)
Sterol 27-hydroxylase activity was inhibited up to -58% after 24 hours of incubation with 140 nmol/L insulin. (eurekamag.com)
To study the mechanism of suppression of cholesterol 7 alpha-hydroxylase and sterol 27-hydroxylase activity, the effects of insulin on their respective levels of messenger RNA (mRNA) and gene transcription were assessed. (eurekamag.com)
The decrease in enzyme activities could be explained by a concomitant reduction in the cholesterol 7 alpha-hydroxylase (-76%) and sterol 27-hydroxylase (-62%) mRNA level. (eurekamag.com)
Transcriptional activity, as assessed by nuclear runoff assays, was decreased to the same extent, i.e., -60% for cholesterol 7 alpha-hydroxylase and -75% for sterol 27-hydroxylase. (eurekamag.com)
In 1980, defects in mitochondrial sterol 27-hydroxylase were implicated in the biochemical pathophysiology of the disease by Oftebro et al. (medscape.com)
The enzymatic defect that causes CTX is in mitochondrial sterol 27-hydroxylase, a key enzyme in the pathway necessary for synthesis of bile acids from cholesterol. (medscape.com)
Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive genetic disorder caused by an abnormality in the CYP27A1 gene, resulting in a deficiency of the mitochondrial enzyme sterol 27-hydroxylase. (rarediseases.org)
sterol 27-hydroxylase). (rarediseases.org)

Cholesterol 7 alpha-hydroxylase also known as cholesterol 7-alpha-monooxygenase or cytochrome P450 7A1 (CYP7A1) is an enzyme that in humans is encoded by the CYP7A1 gene which has an important role in cholesterol metabolism. (wikipedia.org)
The inhibition of cholesterol 7-alpha-hydroxylase (CYP7A1) represses bile acid biosynthesis. (wikipedia.org)
CYP7A1 is located in the endoplasmic reticulum (ER) and is important for the synthesis of bile acid and the regulation of cholesterol levels. (wikipedia.org)
These inflammatory cytokines, which include tumor necrosis factor alpha and interleukin-1beta, act upon the liver parenchymal cells causing a rapid repression of the CYP7A1 gene. (wikipedia.org)
CYP7A1 is upregulated by the nuclear receptor LXR (liver X receptor) when cholesterol (to be specific, oxysterol) levels are high. (wikipedia.org)
The rate-limiting enzyme in the catabolism of cholesterol into bile acids is CYP7A1 (cholesterol 7alpha-hydroxylase). (nih.gov)
The effect of the CYP7A1 A-278C promoter polymorphism on the progression of atherosclerosis, risk of a new clinical event and the influence of this variant on cholesterol-lowering therapy was investigated in 715 male patients with coronary atherosclerosis participating in REGRESS (Regression Growth Evaluation Statin Study). (nih.gov)
Yet, patterns are emerging by studying liver-specific genes in detail, such as the highly regulated gene for the cholesterol 7-hydroxylipase gene ( CYP7A1 ). (kent.edu)
Contributes to the transcriptional repression of cholesterol 7-alpha-hydroxylase (CYP7A1), the rate-limiting enzyme in bile acid synthesis. (nih.gov)

This gene provides instructions for making an enzyme called oxysterol 7-alpha-hydroxylase. (medlineplus.gov)
In the brain, oxysterol 7-alpha-hydroxylase is involved in a pathway that converts cholesterol to hormones called neurosteroids. (medlineplus.gov)
Oxysterol 7-alpha-hydroxylase helps maintain normal cholesterol levels in the brain and, by producing neurosteroids through altering existing hormones within the pathway, regulates the effects of neurosteroids on the brain. (medlineplus.gov)
CYP7B1 gene mutations that cause spastic paraplegia type 5A reduce or eliminate the activity of oxysterol 7-alpha-hydroxylase. (medlineplus.gov)
In the brain, a decrease in enzyme activity results in an accumulation of cholesterol and alters neurosteroid production triggered by oxysterol 7-alpha-hydroxylase. (medlineplus.gov)
In the liver, oxysterol 7-alpha-hydroxylase is involved in the pathway that breaks down a waxy, fat-like substance called cholesterol to form a bile acid called chenodeoxycholic acid. (nih.gov)
Most CYP7B1 gene mutations change single protein building blocks (amino acids) in the oxysterol 7-alpha-hydroxylase enzyme. (nih.gov)
Reduced oxysterol 7-alpha-hydroxylase enzyme activity does not seem to affect cholesterol breakdown or bile acid production in the liver. (nih.gov)
Another pathway in the liver can perform these functions, which may explain why reduction of oxysterol 7-alpha-hydroxylase activity does not impact liver function. (nih.gov)
Together with the oxysterol receptors NR1H3/LXR-alpha and NR1H2/LXR-beta, acts as an essential transcriptional regulator of lipid metabolism. (nih.gov)

Overexpression of cholesterol 7α-hydroxylase (CYP7A) in mice lacking the low density lipoprotein (LDL) receptor gene. (elsevierpure.com)
Dive into the research topics of 'Overexpression of cholesterol 7α-hydroxylase (CYP7A) in mice lacking the low density lipoprotein (LDL) receptor gene. (elsevierpure.com)
Key regulator of cholesterol 7-alpha-hydroxylase gene (CYP7A) expression in liver. (nih.gov)
COUP-TFII stimulates the transcriptional activity of the rat cholesterol 7a-hydroxylase (CYP7A) promoter by binding to the nucleotide sequence located between 74 and 54 (relative to the transcription start site), which contains a direct repeat of two hormone response element half-sites separated by 4 nucleotides. (guidetopharmacology.org)

Cholesterol 7 alpha-hydroxylase is the rate-limiting enzyme in the synthesis of bile acid from cholesterol via the classic pathway, catalyzing the formation of 7α-hydroxycholesterol. (wikipedia.org)
HMG-CoA reductase is a rate-limiting enzyme involved in cholesterol synthesis, while cholesterol 7-alpha hydroxylase is a rate-limiting enzyme involved in the synthesis of bile acid from cholesterol. (heart.news)

In biochemistry , hydroxylation reactions are often facilitated by enzymes called hydroxylases . (wikipedia.org)
These three reactions are catalyzed by very large, multi-subunit enzymes prolyl 4-hydroxylase , prolyl 3-hydroxylase and lysyl 5-hydroxylase , respectively. (wikipedia.org)
They modulate bile flow and lipid secretion, are essential for the absorption of dietary fats and vitamins, and have been implicated in the regulation of all the key enzymes involved in cholesterol homeostasis. (hmdb.ca)

This enzyme, encoded by CYP7, converts cholesterol to 7-alpha-hydroxycholesterol which is the first and rate-limiting step in the synthesis of BILE ACIDS. (nih.gov)
20. Genomic cloning, sequencing, and analysis of the hamster cholesterol 7 alpha-hydroxylase gene (CYP7). (nih.gov)

Transient expression experiments using a construct containing the proximal 348 basepairs of the cholesterol 7 alpha-hydroxylase promoter fused to the chloramphenicol acetyltransferase (CAT) gene (-348Rcat) showed a significant reduction of transcriptional activity (-64%) with insulin, indicating that a sequence important for an insulin-induced transcriptional response is located within the first 348 basepairs, preceding the transcription start of the cholesterol 7 alpha-hydroxylase promoter. (eurekamag.com)

Mechanism of rifampicin and pregnane X receptor inhibition of human cholesterol 7 alpha-hydroxylase gene transcription. (omeka.net)

Primary overexpression of hepatic 7α-hydroxylase in LDL receptor(-/-) mice was accompanied by a dose-dependent decrease in the rate of LDL cholesterol appearance in plasma (whole body LDL cholesterol transport) and a corresponding reduction in circulating LDL cholesterol levels. (elsevierpure.com)
The increase in hepatic 7α-hydroxylase activity necessary to achieve a 50% reduction in plasma LDL cholesterol concentrations was ~10-fold. (elsevierpure.com)
This study demonstrates that augmentation of hepatic 7α-hydroxylase expression is an effective strategy for lowering plasma LDL concentrations even in animals with a genetic absence of LDL receptors. (elsevierpure.com)

The enzyme activity for cholesterol 7 alpha-hydroxylase, examined in more detail, was dose dependently diminished on incubation of hepatocytes with various concentrations of insulin, reaching maximal reduction at 14 nmol/L of insulin. (eurekamag.com)

guanylate binding protein 7 [Source:HGN. (gsea-msigdb.org)

A mitochondrial cytochrome P450 enzyme that catalyzes the side-chain cleavage of C27 cholesterol to C21 pregnenolone in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. (nih.gov)

It is a cytochrome P450 enzyme, which belongs to the oxidoreductase class, and converts cholesterol to 7-alpha-hydroxycholesterol, the first and rate limiting step in bile acid synthesis. (wikipedia.org)
A membrane-bound cytochrome P450 enzyme that catalyzes the 7-alpha-hydroxylation of CHOLESTEROL in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. (nih.gov)
A cytochrome P450 enzyme family whose members function as steroid 7-alpha hydroxylases. (musc.edu)

They also conducted pathological examination of the livers, whole aortas and aortic sinuses of the mice, and measured the expression of proteins related to cholesterol synthesis, absorption and excretion. (heart.news)
The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. (nih.gov)

Cloning, sequencing, and regulation of cholesterol 7 alpha-hydroxylase mRNA. (omeka.net)
And mood or psychiatric disorders the chance of myocarditis or pericarditis occurring after receipt of an mRNA COVID-19 testosterone is a controlled substance which is refillable 3 -7 days prior to being due, depending on the pharmacy. (amiglia.com)

Cholesterol 7-hydroxylase catalyzes the rate-limiting step in the pathway that converts cholesterol to bile acids, and thus controls the amount of cholesterol eliminated from the body. (kent.edu)

With no inhibition of flux into the metabolic pathway, cholesterol-derived bile acid precursors accumulate in tissues and are thought to cause the symptoms of CTX. (medscape.com)

Regulation of cholesterol 7 alpha-hydroxylase in the liver. (omeka.net)
Monospecific antibody against purified rat liver cholesterol 7 alpha-hydroxylase cytochrome P-450 was used to screen a lambda gt11 cDNA library constructed from immuno-enriched polysomal RNA of cholestyramine-treated female rat liver. (omeka.net)
Two cholesterol 7 alpha-hydroxylase isozymes were purified from liver microsomes of cholestyramine-treated female rats by using anion exchange high performance liquid chromatography. (omeka.net)
Sterol 12alpha-hydroxylase (CYP8B1) catalyzes cholic acid synthesis in the liver and is feedback inhibited by bile acids. (omeka.net)
However, the groups that received medium- and high-concentration lactoferrin solutions (MLF and HLF) had significantly reduced serum and liver cholesterol levels compared to the HFCD group. (heart.news)
In isolated rat liver mitochondria, 26-hydroxylation of cholesterol was potently inhibited by the drug (concn. (docksci.com)

24(7)2023 Mar 28. (bvsalud.org)

Cholesterol 7 alpha hydroxylase consists of 491 amino acids, which on folding forms 23 alpha helices and 26 beta sheets. (wikipedia.org)
Stroup, D. & Ramsaran, J. R. Cholesterol 7 alpha-hydroxylase is phosphorylated at multiple amino acids. (kent.edu)

Publication: Quantile-Dependent Expressivity and Gene-Lifestyle Interactions Involving High-Density Lipoprotein Cholesterol. (nih.gov)
The triglyceride level was too high to calculate the low density lipoprotein cholesterol. (biomedcentral.com)

Cholesterol 7 alpha-hydroxylase is a cytochrome P450 heme enzyme that oxidizes cholesterol in the position 7 using molecular oxygen. (wikipedia.org)

Journal of Biological Chemistry, 267 (7), 4759-4765. (atilravillaallende.com.ar)

In the livers of lactoferrin-treated mice, the researchers observed a decrease in the expression of HMG-CoA reductase and an increase in the expression of cholesterol 7-alpha hydroxylase. (heart.news)

This reduction was accompanied by a significant increase in their fecal cholesterol content, suggesting that lactoferrin helps reduce cholesterol levels by promoting its excretion. (heart.news)

The enzyme primarily converts the neurosteroid dehydroepiandrosterone (DHEA) into 7-hydroxy-DHEA. (nih.gov)

Cytokine regulation of human sterol 12alpha-hydroxylase (CYP8B1) gene. (omeka.net)

The lack of this enzyme prevents cholesterol from being converted into a bile acid called chenodeoxycholic acid. (rarediseases.org)

Pathways as wide ranging as cholesterol synthesis, apolipoprotein gene expression, and cholesterol catabolism are coordinately regulated by mechanisms not clearly understood. (kent.edu)
Bile acids can be formed from cholesterol via different pathways, as has been shown in studies with radiolabelled intermediates in vivo and in vitro [10]. (docksci.com)
Although the route starting with 7a-hydroxylation of cholesterol is considered to be quantitatively the most important one for formation of bile acids, alternative pathways can exist, particularly for the synthesis of chenodeoxycholic acid. (docksci.com)

5] This led to successful trials of therapy with CDCA replacement, in 1975 by Salen[6] and later with Berginer,[7] that was found to normalize the biochemical phenotype and prevent disease progression. (medscape.com)

Stroup, D. & Nnamani, M. C. The orphan nuclear receptor, alpha-fetoprotein transcription factor (FTF), is phosphorylated by protein kinases. (kent.edu)
7. Structure and expression of the Kas12 gene encoding a beta-ketoacyl-acyl carrier protein synthase I isozyme from barley. (nih.gov)
To determine if lactoferrin can prevent or inhibit the progression of atherosclerosis - a serious heart condition caused by the buildup of cholesterol in the arteries - the Chinese researchers decided to test lactoferrin on mice genetically engineered to be deficient in apoprotein E (apoE), a protein involved in the metabolism of lipids. (heart.news)
Lactoferrin also decreased the expression of Niemann-Pick C1-like 1 protein, which binds to a critical mediator of cholesterol absorption in the intestines. (heart.news)
This endoplasmic reticulum membrane protein catalyzes the first reaction in the cholesterol catabolic pathway of extrahepatic tissues, which converts cholesterol to bile acids. (nih.gov)

The effect of this upregulation is to increase the production of bile acids and reduce the level of cholesterol in hepatocytes. (wikipedia.org)
The mature bile acids (primarily CDCA) are responsible for negative feedback on cholesterol 7-alpha-hydroxylase, which is the initial and rate-limiting step in bile acid synthesis. (medscape.com)
Materials and animals Materials used for the isolation and culture of rat and human hepatocytes, determination of bile acid synthesis from radiolabelled cholesterol, measurement of mass production of bile acids, the cholesterol 7a-hydroxylase activity and other enzyme assays were obtained from sources described previously [19-21]. (docksci.com)
The distinction between different bile acids is minute, depending only on the presence or absence of hydroxyl groups on positions 3, 7, and 12. (hmdb.ca)
Bile acids are also steroidal amphipathic molecules derived from the catabolism of cholesterol. (hmdb.ca)

The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis. (nih.gov)
Based on these findings, the researchers concluded that lactoferrin alleviates atherosclerosis by decreasing cholesterol synthesis and absorption and increasing cholesterol excretion. (heart.news)

An enzyme that catalyzes the oxidation of cholesterol in the presence of molecular oxygen to 4-cholesten-3-one and hydrogen peroxide. (nih.gov)

Clin Cancer Res 2001;7:1894-900. (therapeuticresearch.com)
Food Chem Toxicol 2001;39:541-7. (therapeuticresearch.com)

Bile acid synthesis is the most significant pathway for catabolism of cholesterol and for maintenance of whole body cholesterol homeostasis. (omeka.net)

An autosomal recessive disorder of lipoprotein metabolism caused by mutation of LECITHIN CHOLESTEROL ACYLTRANSFERASE gene. (nih.gov)
Abnormal cholesterol metabolism is related to many serious and common health problems, including heart attack, stroke, and cholesterol gallstones. (kent.edu)
Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder of cholesterol and bile acid metabolism that results in systemic and neurologic abnormalities. (medscape.com)
Tsuyoshi Goto, Scope: Peroxisome proliferator-activated receptor alpha (PPAR-α) is a ligand-activated transcription factor that regulates lipid and carbohydrate metabolism. (nara-wu.ac.jp)

Insulin strongly reduced the rise in cholesterol 7 alpha-hydroxylase activity induced by incubation with dexamethasone. (eurekamag.com)
Cholesterol 7-hydroxylase is clearly phosphorylated and this phosphorylation increases the enzyme's synthetic activity. (kent.edu)
Due to post-cycle hormone imbalances associated with substances and they also face sanctions from progesterone were used as an indication for 17-hydroxylase and 17,20-lyase activity (23). (theopeninter.net)

It is characterized by the accumulation of neutral lipids, particularly CHOLESTEROL ESTERS in leukocytes, fibroblasts, and hepatocytes. (nih.gov)

Sequence alterations within CYP7B1 implicate defective cholesterol homeostasis in motor-neuron degeneration. (nih.gov)
Nuclear receptor that acts as a key metabolic sensor by regulating the expression of genes involved in bile acid synthesis, cholesterol homeostasis and triglyceride synthesis. (nih.gov)

The abnormal buildup of cholesterol in the brain probably also contributes to the death of nerve cells. (medlineplus.gov)

In this study, Balb/c mice (male, 7 weeks old) were fed a pellet HFD (43% fat, 20 kJ/g) for 16 weeks when exposed to nicotine or nicotine-free e-vapour from weeks 11 to 16. (bvsalud.org)
The researchers fed 48 apoE-deficient mice with a high-fat diet that contained 1.25 percent added cholesterol. (heart.news)

Cholesterol which is contained in or bound to very low density lipoproteins (VLDL). (nih.gov)
The cholesterol on the VLDL is eventually delivered by LOW-DENSITY LIPOPROTEINS to the tissues after the catabolism of VLDL to INTERMEDIATE-DENSITY LIPOPROTEINS, then to LDL. (nih.gov)
Cholesterol which is contained in or bound to low density lipoproteins (LDL), including CHOLESTEROL ESTERS and free cholesterol . (nih.gov)
BACKGROUND: The phenotypic expression of a high-density lipoprotein (HDL) genetic risk score has been shown to depend upon whether the phenotype (HDL-cholesterol) is high or low relative to its distribution in the population (quantile-dependent expressivity). (nih.gov)

Anatomy14

Organisms7

Diseases13

Chemicals and Drugs114

Analytical, Diagnostic and Therapeutic Techniques and Equipment10

Phenomena and Processes29

Disciplines and Occupations1

Technology, Industry, Agriculture5

Information Science3

Health Care1

Sterol 27-hydroxyl10

CYP7A19

Oxysterol10

CYP7A4

Rate-limiti2

Enzymes3

CYP72

Promoter1

Gene transcription1

Hepatic3

Enzyme activity1

Source:HGN1

Mitochondrial1

Cytochrome P450 enzyme3

Proteins2

MRNA2

Pathway that converts cholesterol1

Inhibition1

Liver6

20231

Amino2

Lipoprotein Cholesterol2

Heme1

Journal of Biolog1

REDUCTASE1

Reduction1

Neurosteroid1

Regulation1

Bile acid called chenodeoxycholic acid1

Pathways3

19751

Protein5

ACIDS5

Atherosclerosis2

Molecular oxygen1

20012

Catabolism of cholesterol1

Metabolism4

Activity3

Hepatocytes1

Homeostasis2

Buildup of cholesterol1

Mice2

Density4