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Farnesoid X Receptor
The bile acid receptor (BAR), also known as farnesoid X receptor (FXR) or NR1H4 (nuclear receptor subfamily 1, group H, member 4), is a nuclear receptor that is encoded by the ''NR1H4'' gene in humans. Function FXR is expressed at high levels in the liver and intestine. Chenodeoxycholic acid and other bile acids are natural ligands for FXR. Similar to other nuclear receptors, when activated, FXR translocates to the cell nucleus, forms a dimer (in this case a heterodimer with RXR) and binds to hormone response elements on DNA, which up- or down-regulates the expression of certain genes. One of the primary functions of FXR activation is the suppression of cholesterol 7 alpha-hydroxylase (CYP7A1), the rate-limiting enzyme in bile acid synthesis from cholesterol. FXR does not directly bind to the ''CYP7A1'' promoter. Rather, FXR induces expression of small heterodimer partner (SHP), which then functions to inhibit transcription of the ''CYP7A1'' gene. FXR likewise stimula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Receptor
In the field of molecular biology, nuclear receptors are a class of proteins responsible for sensing steroids, thyroid hormones, vitamins, and certain other molecules. These intracellular receptors work with other proteins to regulate the expression of specific genes, thereby controlling the development, homeostasis, and metabolism of the organism. Nuclear receptors bind directly to DNA regulating the expression of adjacent genes; hence these receptors are classified as transcription factors. The regulation of gene expression by nuclear receptors often occurs in the presence of a ligand—a molecule that affects the receptor's behavior. Ligand binding to a nuclear receptor results in a conformational change activating the receptor. The result is up- or down-regulation of gene expression. A unique property of nuclear receptors that differentiates them from other classes of receptors is their direct control of genomic DNA. Nuclear receptors play key roles in both embryonic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholestyramine
Colestyramine ( INN) or cholestyramine ( USAN) (trade names Questran, Questran Light, Cholybar, Olestyr, Quantalan, Vasosan) is a bile acid sequestrant, which binds bile in the gastrointestinal tract to prevent its reabsorption. It is a strong ion exchange resin, which means it can exchange its chloride anions with anionic bile acids in the gastrointestinal tract and bind them strongly in the resin matrix. The functional group of the anion exchange resin is a quaternary ammonium group attached to an inert styrene- divinylbenzene copolymer. Colestyramine removes bile acids from the body by forming insoluble complexes with bile acids in the intestine, which are then excreted in the feces. As a result of this loss of bile acids, more plasma cholesterol is converted to bile acids in the liver to normalise levels. This conversion of cholesterol into bile acids lowers plasma cholesterol levels. Medical uses Bile acid sequestrants such as colestyramine were first used to treat hype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cafestol
Cafestol is a diterpenoid molecule present in coffee beans. It is one of the compounds that may be responsible for proposed biological and pharmacological effects of coffee. Sources A typical bean of ''Coffea arabica'' contains about 0.4% to 0.7% cafestol by weight. Cafestol is present in highest quantity in unfiltered coffee drinks such as French press coffee, and Turkish coffee. In paper-filtered coffee drinks such as drip brewed coffee, it is present in only negligible amounts, as the paper filter in drip filtered coffee retains the diterpenes. Research into biological activity Coffee consumption has been associated with a number of effects on health and cafestol has been proposed to produce these through a number of biological actions. Studies have shown that regular consumption of boiled coffee increases serum cholesterol whereas filtered coffee does not. Cafestol may act as an agonist ligand for the nuclear receptor farnesoid X receptor and pregnane X receptor, bl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinoid X Receptor Alpha
Retinoid X receptor alpha (RXR-alpha), also known as NR2B1 (nuclear receptor subfamily 2, group B, member 1) is a nuclear receptor that in humans is encoded by the ''RXRA'' gene. Function Retinoid X receptors (RXRs) and retinoic acid receptors (RARs), are nuclear receptors that mediate the biological effects of retinoids by their involvement in retinoic acid-mediated gene activation. These receptors exert their action by binding, as homodimers or heterodimers, to specific sequences in the promoters of target genes and regulating their transcription. The protein encoded by this gene is a member of the steroid and thyroid hormone receptor superfamily of transcription factors. In the absence of ligand, the RXR-RAR heterodimers associate with a multiprotein complex containing transcription corepressors that induce histone deacetylation, chromatin condensation and transcriptional suppression. On ligand binding, the corepressors dissociate from the receptors and associate with the co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogenesis
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cell (biology), cells are malignant transformation, transformed into cancer cells. The process is characterized by changes at the cellular, Genetics, genetic, and Epigenetics, epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all Tissue (biology), tissues and under a variety of circumstances. Normally, the balance between proliferation and programmed cell death, in the form of apoptosis, is maintained to ensure the integrity of tissues and Organ (anatomy), organs. According to the prevailing accepted theory of carcinogenesis, the somatic mutation theory, mutations in DNA and Epigenetics, epimutations that lead to cancer disrupt these orderly processes by interfering with the programming regulating the processes, upsetting the normal balance between proliferation and cell death. This results in uncontrolled cell division ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenocarcinoma
Adenocarcinoma (; plural adenocarcinomas or adenocarcinomata ; AC) is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or both. Adenocarcinomas are part of the larger grouping of carcinomas, but are also sometimes called by more precise terms omitting the word, where these exist. Thus invasive ductal carcinoma, the most common form of breast cancer, is adenocarcinoma but does not use the term in its name—however, esophageal adenocarcinoma does to distinguish it from the other common type of esophageal cancer, esophageal squamous cell carcinoma. Several of the most common forms of cancer are adenocarcinomas, and the various sorts of adenocarcinoma vary greatly in all their aspects, so that few useful generalizations can be made about them. In the most specific usage, the glandular origin or traits are exocrine; endocrine gland tumors, such as a VIPoma, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulin Resistance
Insulin resistance (IR) is a pathological response in which cells in insulin-sensitive tissues in the body fail to respond normally to the hormone insulin or downregulate insulin receptors in response to hyperinsulinemia. Insulin is a hormone that facilitates the transport of glucose from blood into cells, thereby reducing blood glucose (blood sugar). Insulin is released by the pancreas in response to carbohydrates consumed in the diet. In states of insulin resistance, the same amount of insulin does not have the same effect on glucose transport and blood sugar levels. There are many causes of insulin resistance and the underlying process is still not completely understood. Risk factors for insulin resistance include obesity, sedentary lifestyle, family history of diabetes, various health conditions, and certain medications. Insulin resistance is considered a component of the metabolic syndrome. Insulin resistance can be improved or reversed with lifestyle approaches, such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cystic Fibrosis Transmembrane Conductance Regulator
Cystic fibrosis transmembrane conductance regulator (CFTR) is a membrane protein and anion channel in vertebrates that is encoded by the ''CFTR'' gene. Geneticist Lap-Chee Tsui and his team identified the ''CFTR'' gene in 1989 as the gene linked with CF (cystic fibrosis). The ''CFTR'' gene codes for an ABC transporter-class ion channel protein that conducts chloride and bicarbonate ions across epithelial cell membranes. Mutations of the ''CFTR'' gene affecting anion channel function lead to dysregulation of epithelial lining fluid (mucus) transport in the lung, pancreas and other organs, resulting in cystic fibrosis. Complications include thickened mucus in the lungs with frequent respiratory infections, and pancreatic insufficiency giving rise to malnutrition and diabetes. These conditions lead to chronic disability and reduced life expectancy. In male patients, the progressive obstruction and destruction of the developing vas deferens (spermatic cord) and epididymis appe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peroxisome Proliferator-activated Receptor Alpha
Peroxisome proliferator-activated receptor alpha (PPAR-α), also known as NR1C1 (nuclear receptor subfamily 1, group C, member 1), is a nuclear receptor protein functioning as a transcription factor that in humans is encoded by the ''PPARA'' gene. Together with peroxisome proliferator-activated receptor delta and peroxisome proliferator-activated receptor gamma, PPAR-alpha is part of the subfamily of peroxisome proliferator-activated receptors. It was the first member of the PPAR family to be cloned in 1990 by Stephen Green and has been identified as the nuclear receptor for a diverse class of rodent Liver, hepatocarcinogens that causes proliferation of peroxisomes. Expression PPAR-α is primarily activated through ligand binding. Endogenous ligands include fatty acids such as arachidonic acid as well as other polyunsaturated fatty acids and various fatty acid-derived compounds such as certain members of the 15-hydroxyicosatetraenoic acid, 15-hydroxyeicosatetraenoic acid family ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. The oxidation and reduction processes occur simultaneously in the chemical reaction. There are two classes of redox reactions: * Electron-transfer – Only one (usually) electron flows from the atom, ion, or molecule being oxidized to the atom, ion, or molecule that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * Atom transfer – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously, the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
