Microsomes, Liver: Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.Microsomes: Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Liver Diseases: Pathological processes of the LIVER.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Liver Transplantation: The transference of a part of or an entire liver from one human or animal to another.Liver Neoplasms: Tumors or cancer of the LIVER.Liver Cirrhosis: Liver disease in which the normal microcirculation, the gross vascular anatomy, and the hepatic architecture have been variably destroyed and altered with fibrous septa surrounding regenerated or regenerating parenchymal nodules.Cytochrome P-450 Enzyme System: A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.Liver Regeneration: Repair or renewal of hepatic tissue.Fatty Liver: Lipid infiltration of the hepatic parenchymal cells resulting in a yellow-colored liver. The abnormal lipid accumulation is usually in the form of TRIGLYCERIDES, either as a single large droplet or multiple small droplets. Fatty liver is caused by an imbalance in the metabolism of FATTY ACIDS.Biotransformation: The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.Mitochondria, Liver: Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)Hydroxylation: Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)Liver Function Tests: Blood tests that are used to evaluate how well a patient's liver is working and also to help diagnose liver conditions.Drug-Induced Liver Injury: A spectrum of clinical liver diseases ranging from mild biochemical abnormalities to ACUTE LIVER FAILURE, caused by drugs, drug metabolites, and chemicals from the environment.Glucuronosyltransferase: A family of enzymes accepting a wide range of substrates, including phenols, alcohols, amines, and fatty acids. They function as drug-metabolizing enzymes that catalyze the conjugation of UDPglucuronic acid to a variety of endogenous and exogenous compounds. EC 2.4.1.17.Mixed Function Oxygenases: Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.Cytochrome P-450 CYP3A: A cytochrome P-450 suptype that has specificity for a broad variety of lipophilic compounds, including STEROIDS; FATTY ACIDS; and XENOBIOTICS. This enzyme has clinical significance due to its ability to metabolize a diverse array of clinically important drugs such as CYCLOSPORINE; VERAPAMIL; and MIDAZOLAM. This enzyme also catalyzes the N-demethylation of ERYTHROMYCIN.Aryl Hydrocarbon Hydroxylases: A large group of cytochrome P-450 (heme-thiolate) monooxygenases that complex with NAD(P)H-FLAVIN OXIDOREDUCTASE in numerous mixed-function oxidations of aromatic compounds. They catalyze hydroxylation of a broad spectrum of substrates and are important in the metabolism of steroids, drugs, and toxins such as PHENOBARBITAL, carcinogens, and insecticides.Glucuronides: Glycosides of GLUCURONIC ACID formed by the reaction of URIDINE DIPHOSPHATE GLUCURONIC ACID with certain endogenous and exogenous substances. Their formation is important for the detoxification of drugs, steroid excretion and BILIRUBIN metabolism to a more water-soluble compound that can be eliminated in the URINE and BILE.Kinetics: The rate dynamics in chemical or physical systems.Dealkylation: The removing of alkyl groups from a compound. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Liver Neoplasms, Experimental: Experimentally induced tumors of the LIVER.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Liver Extracts: Extracts of liver tissue containing uncharacterized specific factors with specific activities; a soluble thermostable fraction of mammalian liver is used in the treatment of pernicious anemia.Liver Circulation: The circulation of BLOOD through the LIVER.Phenobarbital: A barbituric acid derivative that acts as a nonselective central nervous system depressant. It potentiates GAMMA-AMINOBUTYRIC ACID action on GABA-A RECEPTORS, and modulates chloride currents through receptor channels. It also inhibits glutamate induced depolarizations.Hepatocytes: The main structural component of the LIVER. They are specialized EPITHELIAL CELLS that are organized into interconnected plates called lobules.Oxidoreductases, N-DemethylatingChromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Liver Failure, Acute: A form of rapid-onset LIVER FAILURE, also known as fulminant hepatic failure, caused by severe liver injury or massive loss of HEPATOCYTES. It is characterized by sudden development of liver dysfunction and JAUNDICE. Acute liver failure may progress to exhibit cerebral dysfunction even HEPATIC COMA depending on the etiology that includes hepatic ISCHEMIA, drug toxicity, malignant infiltration, and viral hepatitis such as post-transfusion HEPATITIS B and HEPATITIS C.NADPH-Ferrihemoprotein Reductase: A flavoprotein that catalyzes the reduction of heme-thiolate-dependent monooxygenases and is part of the microsomal hydroxylating system. EC 1.6.2.4.Liver Abscess: Solitary or multiple collections of PUS within the liver as a result of infection by bacteria, protozoa, or other agents.Liver Diseases, Alcoholic: Liver diseases associated with ALCOHOLISM. It usually refers to the coexistence of two or more subentities, i.e., ALCOHOLIC FATTY LIVER; ALCOHOLIC HEPATITIS; and ALCOHOLIC CIRRHOSIS.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.NADP: Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)Ketoconazole: Broad spectrum antifungal agent used for long periods at high doses, especially in immunosuppressed patients.Troleandomycin: A macrolide antibiotic that is similar to ERYTHROMYCIN.Steroid Hydroxylases: Cytochrome P-450 monooxygenases (MIXED FUNCTION OXYGENASES) that are important in steroid biosynthesis and metabolism.Steroid 16-alpha-Hydroxylase: A liver microsomal cytochrome P450 enzyme that catalyzes the 16-alpha-hydroxylation of a broad spectrum of steroids, fatty acids, and xenobiotics in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme is encoded by a number of genes from several CYP2 subfamilies.Hepatectomy: Excision of all or part of the liver. (Dorland, 28th ed)Benzoflavones: Organic compounds containing a BENZENE ring attached to a flavone group. Some of these are potent arylhydrocarbon hydroxylase inhibitors. They may also inhibit the binding of NUCLEIC ACIDS to BENZOPYRENES and related compounds. The designation includes all isomers; the 7,8-isomer is most frequently encountered.Cytochrome P-450 CYP1A2: A cytochrome P450 enzyme subtype that has specificity for relatively planar heteroaromatic small molecules, such as CAFFEINE and ACETAMINOPHEN.Uridine Diphosphate Glucuronic Acid: A nucleoside diphosphate sugar which serves as a source of glucuronic acid for polysaccharide biosynthesis. It may also be epimerized to UDP iduronic acid, which donates iduronic acid to polysaccharides. In animals, UDP glucuronic acid is used for formation of many glucosiduronides with various aglycones.Methylcholanthrene: A carcinogen that is often used in experimental cancer studies.Liver Cirrhosis, Experimental: Experimentally induced chronic injuries to the parenchymal cells in the liver to achieve a model for LIVER CIRRHOSIS.Cytochrome P-450 CYP2E1: An ethanol-inducible cytochrome P450 enzyme that metabolizes several precarcinogens, drugs, and solvents to reactive metabolites. Substrates include ETHANOL; INHALATION ANESTHETICS; BENZENE; ACETAMINOPHEN and other low molecular weight compounds. CYP2E1 has been used as an enzyme marker in the study of alcohol abuse.Proadifen: An inhibitor of drug metabolism and CYTOCHROME P-450 ENZYME SYSTEM activity.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Liver Cirrhosis, Alcoholic: FIBROSIS of the hepatic parenchyma due to chronic excess ALCOHOL DRINKING.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Cytochrome P-450 CYP2D6: A cytochrome P450 enzyme that catalyzes the hydroxylation of many drugs and environmental chemicals, such as DEBRISOQUINE; ADRENERGIC RECEPTOR ANTAGONISTS; and TRICYCLIC ANTIDEPRESSANTS. This enzyme is deficient in up to 10 percent of the Caucasian population.Liver, Artificial: Devices for simulating the activities of the liver. They often consist of a hybrid between both biological and artificial materials.Liver Glycogen: Glycogen stored in the liver. (Dorland, 28th ed)Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Alanine Transaminase: An enzyme that catalyzes the conversion of L-alanine and 2-oxoglutarate to pyruvate and L-glutamate. (From Enzyme Nomenclature, 1992) EC 2.6.1.2.Cytochrome ReductasesEnzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Carcinoma, Hepatocellular: A primary malignant neoplasm of epithelial liver cells. It ranges from a well-differentiated tumor with EPITHELIAL CELLS indistinguishable from normal HEPATOCYTES to a poorly differentiated neoplasm. The cells may be uniform or markedly pleomorphic, or form GIANT CELLS. Several classification schemes have been suggested.End Stage Liver Disease: Final stage of a liver disease when the liver failure is irreversible and LIVER TRANSPLANTATION is needed.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Glucose-6-Phosphatase: An enzyme that catalyzes the conversion of D-glucose 6-phosphate and water to D-glucose and orthophosphate. EC 3.1.3.9.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Coumarins: Synthetic or naturally occurring substances related to coumarin, the delta-lactone of coumarinic acid.Sulfaphenazole: A sulfonilamide anti-infective agent.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Cytochromes b5: Cytochromes of the b group that are found bound to cytoplasmic side of ENDOPLASMIC RETICULUM. They serve as electron carrier proteins for a variety of membrane-bound OXYGENASES. They are reduced by the enzyme CYTOCHROME-B(5) REDUCTASE.beta-Naphthoflavone: A polyaromatic hydrocarbon inducer of P4501A1 and P4501A2 cytochromes. (Proc Soc Exp Biol Med 1994 Dec:207(3):302-308)RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Glucuronates: Derivatives of GLUCURONIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that include the 6-carboxy glucose structure.Subcellular Fractions: Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Carbon Tetrachloride: A solvent for oils, fats, lacquers, varnishes, rubber waxes, and resins, and a starting material in the manufacturing of organic compounds. Poisoning by inhalation, ingestion or skin absorption is possible and may be fatal. (Merck Index, 11th ed)Oxygenases: Oxidases that specifically introduce DIOXYGEN-derived oxygen atoms into a variety of organic molecules.Rats, Inbred F344Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Intracellular Membranes: Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.Metabolic Detoxication, Phase I: Functionalization of exogenous substances to prepare them for conjugation in PHASE II DETOXIFICATION. Phase I enzymes include CYTOCHROME P450 enzymes and some OXIDOREDUCTASES. Excess induction of phase I over phase II detoxification leads to higher levels of FREE RADICALS that can induce CANCER and other cell damage. Induction or antagonism of phase I detoxication is the basis of a number of DRUG INTERACTIONS.Phenacetin: A phenylacetamide that was formerly used in ANALGESICS but nephropathy and METHEMOGLOBINEMIA led to its withdrawal from the market. (From Smith and Reynard, Textbook of Pharmacology,1991, p431)Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Endoplasmic Reticulum: A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)Benzopyrene Hydroxylase: A drug-metabolizing, cytochrome P-448 (P-450) enzyme which catalyzes the hydroxylation of benzopyrene to 3-hydroxybenzopyrene in the presence of reduced flavoprotein and molecular oxygen. Also acts on certain anthracene derivatives. An aspect of EC 1.14.14.1.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Recombinant Proteins: Proteins prepared by recombinant DNA technology.Carcinogens: Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.Nitrosamines: A class of compounds that contain a -NH2 and a -NO radical. Many members of this group have carcinogenic and mutagenic properties.Tissue Distribution: Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.Hepatitis: INFLAMMATION of the LIVER.Bilirubin: A bile pigment that is a degradation product of HEME.Benzopyrenes: A class of chemicals that contain an anthracene ring with a naphthalene ring attached to it.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Acyltransferases: Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.Glutathione: A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.Chlorzoxazone: A centrally acting central muscle relaxant with sedative properties. It is claimed to inhibit muscle spasm by exerting an effect primarily at the level of the spinal cord and subcortical areas of the brain. (From Martindale, The Extra Pharmacopoea, 30th ed, p1202)Metabolic Detoxication, Drug: Reduction of pharmacologic activity or toxicity of a drug or other foreign substance by a living system, usually by enzymatic action. It includes those metabolic transformations that make the substance more soluble for faster renal excretion.Dolichol: Eicosamethyl octacontanonadecasen-1-o1. Polyprenol found in animal tissues that contains about 20 isoprene residues, the one carrying the alcohol group being saturated.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Dimethylnitrosamine: A nitrosamine derivative with alkylating, carcinogenic, and mutagenic properties. It causes serious liver damage and is a hepatocarcinogen in rodents.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Bile: An emulsifying agent produced in the LIVER and secreted into the DUODENUM. Its composition includes BILE ACIDS AND SALTS; CHOLESTEROL; and ELECTROLYTES. It aids DIGESTION of fats in the duodenum.Kupffer Cells: Specialized phagocytic cells of the MONONUCLEAR PHAGOCYTE SYSTEM found on the luminal surface of the hepatic sinusoids. They filter bacteria and small foreign proteins out of the blood, and dispose of worn out red blood cells.Quinidine: An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.Membranes: Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.Phospholipids: Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.7-Alkoxycoumarin O-Dealkylase: A drug-metabolizing enzyme found in the hepatic, placental and intestinal microsomes that metabolizes 7-alkoxycoumarin to 7-hydroxycoumarin. The enzyme is cytochrome P-450- dependent.Carboxylesterase: Carboxylesterase is a serine-dependent esterase with wide substrate specificity. The enzyme is involved in the detoxification of XENOBIOTICS and the activation of ester and of amide PRODRUGS.Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Lipid Metabolism: Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.Ethanol: A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.Organ Specificity: Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.Safrole: A member of the BENZODIOXOLES that is a constituent of several VOLATILE OILS, notably SASSAFRAS oil. It is a precursor in the synthesis of the insecticide PIPERONYL BUTOXIDE and the drug N-methyl-3,4-methylenedioxyamphetamine (MDMA).Organ Size: The measurement of an organ in volume, mass, or heaviness.Carboxylic Ester Hydrolases: Enzymes which catalyze the hydrolysis of carboxylic acid esters with the formation of an alcohol and a carboxylic acid anion.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Portal Vein: A short thick vein formed by union of the superior mesenteric vein and the splenic vein.Cell Fractionation: Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.Intestines: The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE.Carbon Radioisotopes: Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.Cytochrome P-450 CYP2B1: A major cytochrome P-450 enzyme which is inducible by PHENOBARBITAL in both the LIVER and SMALL INTESTINE. It is active in the metabolism of compounds like pentoxyresorufin, TESTOSTERONE, and ANDROSTENEDIONE. This enzyme, encoded by CYP2B1 gene, also mediates the activation of CYCLOPHOSPHAMIDE and IFOSFAMIDE to MUTAGENS.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Polyisoprenyl Phosphate Monosaccharides: These compounds function as activated monosaccharide carriers in the biosynthesis of glycoproteins and oligosaccharide phospholipids. Obtained from a nucleoside diphosphate sugar and a polyisoprenyl phosphate.Carbon Tetrachloride PoisoningDNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Palmitoyl Coenzyme A: A fatty acid coenzyme derivative which plays a key role in fatty acid oxidation and biosynthesis.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Acetaminophen: Analgesic antipyretic derivative of acetanilide. It has weak anti-inflammatory properties and is used as a common analgesic, but may cause liver, blood cell, and kidney damage.Lipid Peroxides: Peroxides produced in the presence of a free radical by the oxidation of unsaturated fatty acids in the cell in the presence of molecular oxygen. The formation of lipid peroxides results in the destruction of the original lipid leading to the loss of integrity of the membranes. They therefore cause a variety of toxic effects in vivo and their formation is considered a pathological process in biological systems. Their formation can be inhibited by antioxidants, such as vitamin E, structural separation or low oxygen tension.Epoxide Hydrolases: Enzymes that catalyze reversibly the formation of an epoxide or arene oxide from a glycol or aromatic diol, respectively.Aflatoxin B1: A potent hepatotoxic and hepatocarcinogenic mycotoxin produced by the Aspergillus flavus group of fungi. It is also mutagenic, teratogenic, and causes immunosuppression in animals. It is found as a contaminant in peanuts, cottonseed meal, corn, and other grains. The mycotoxin requires epoxidation to aflatoxin B1 2,3-oxide for activation. Microsomal monooxygenases biotransform the toxin to the less toxic metabolites aflatoxin M1 and Q1.Benzphetamine: A sympathomimetic agent with properties similar to DEXTROAMPHETAMINE. It is used in the treatment of obesity. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1222)Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Acyl Coenzyme A: S-Acyl coenzyme A. Fatty acid coenzyme A derivatives that are involved in the biosynthesis and oxidation of fatty acids as well as in ceramide formation.2-Acetylaminofluorene: A hepatic carcinogen whose mechanism of activation involves N-hydroxylation to the aryl hydroxamic acid followed by enzymatic sulfonation to sulfoxyfluorenylacetamide. It is used to study the carcinogenicity and mutagenicity of aromatic amines.Clofibrate: A fibric acid derivative used in the treatment of HYPERLIPOPROTEINEMIA TYPE III and severe HYPERTRIGLYCERIDEMIA. (From Martindale, The Extra Pharmacopoeia, 30th ed, p986)Hepatic Artery: A branch of the celiac artery that distributes to the stomach, pancreas, duodenum, liver, gallbladder, and greater omentum.Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Bile Ducts: The channels that collect and transport the bile secretion from the BILE CANALICULI, the smallest branch of the BILIARY TRACT in the LIVER, through the bile ductules, the bile ducts out the liver, and to the GALLBLADDER for storage.Immunochemistry: Field of chemistry that pertains to immunological phenomena and the study of chemical reactions related to antigen stimulation of tissues. It includes physicochemical interactions between antigens and antibodies.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Chromatography, Liquid: Chromatographic techniques in which the mobile phase is a liquid.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Orphenadrine: A muscarinic antagonist used to treat drug-induced parkinsonism and to relieve pain from muscle spasm.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.NAD: A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)Aminopyrine N-DemethylaseCytochromes: Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.Mutagens: Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.Midazolam: A short-acting hypnotic-sedative drug with anxiolytic and amnestic properties. It is used in dentistry, cardiac surgery, endoscopic procedures, as preanesthetic medication, and as an adjunct to local anesthesia. The short duration and cardiorespiratory stability makes it useful in poor-risk, elderly, and cardiac patients. It is water-soluble at pH less than 4 and lipid-soluble at physiological pH.Cytochrome-B(5) Reductase: A FLAVOPROTEIN oxidoreductase that occurs both as a soluble enzyme and a membrane-bound enzyme due to ALTERNATIVE SPLICING of a single mRNA. The soluble form is present mainly in ERYTHROCYTES and is involved in the reduction of METHEMOGLOBIN. The membrane-bound form of the enzyme is found primarily in the ENDOPLASMIC RETICULUM and outer mitochondrial membrane, where it participates in the desaturation of FATTY ACIDS; CHOLESTEROL biosynthesis and drug metabolism. A deficiency in the enzyme can result in METHEMOGLOBINEMIA.Living Donors: Non-cadaveric providers of organs for transplant to related or non-related recipients.Diethylnitrosamine: A nitrosamine derivative with alkylating, carcinogenic, and mutagenic properties.Metabolic Clearance Rate: Volume of biological fluid completely cleared of drug metabolites as measured in unit time. Elimination occurs as a result of metabolic processes in the kidney, liver, saliva, sweat, intestine, heart, brain, or other site.Oxidoreductases, O-Demethylating: Drug metabolizing enzymes which oxidize methyl ethers. Usually found in liver microsomes.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Alkane 1-Monooxygenase: A P450 oxidoreductase that catalyzes the hydroxylation of the terminal carbon of linear hydrocarbons such as octane and FATTY ACIDS in the omega position. The enzyme may also play a role in the oxidation of a variety of structurally unrelated compounds such as XENOBIOTICS, and STEROIDS.Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Chromatography, Thin Layer: Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)TritiumBlotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Epoxy Compounds: Organic compounds that include a cyclic ether with three ring atoms in their structure. They are commonly used as precursors for POLYMERS such as EPOXY RESINS.gamma-Glutamyltransferase: An enzyme, sometimes called GGT, with a key role in the synthesis and degradation of GLUTATHIONE; (GSH, a tripeptide that protects cells from many toxins). It catalyzes the transfer of the gamma-glutamyl moiety to an acceptor amino acid.Bile Acids and Salts: Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Aroclors: Industrial chemicals which have become widespread environmental pollutants. Each aroclor is a mixture of chlorinated biphenyls (1200 series) or chlorinated terphenyls (5400 series) or a combination of both (4400 series).Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Cholestasis: Impairment of bile flow due to obstruction in small bile ducts (INTRAHEPATIC CHOLESTASIS) or obstruction in large bile ducts (EXTRAHEPATIC CHOLESTASIS).Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Dolichol Phosphates: Phosphoric acid esters of dolichol.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Anisoles: A group of compounds that are derivatives of methoxybenzene and contain the general formula R-C7H7O.Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.Mutagenicity Tests: Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Acetone: A colorless liquid used as a solvent and an antiseptic. It is one of the ketone bodies produced during ketoacidosis.Rats, Gunn: Mutant strain of Rattus norvegicus which is used as a disease model of kernicterus.Cytochrome P-450 CYP1A1: A liver microsomal cytochrome P-450 monooxygenase capable of biotransforming xenobiotics such as polycyclic hydrocarbons and halogenated aromatic hydrocarbons into carcinogenic or mutagenic compounds. They have been found in mammals and fish. This enzyme, encoded by CYP1A1 gene, can be measured by using ethoxyresorufin as a substrate for the ethoxyresorufin O-deethylase activity.Liver Abscess, Pyogenic: Single or multiple areas of PUS due to bacterial infection within the hepatic parenchyma. It can be caused by a variety of BACTERIA, local or disseminated from infections elsewhere such as in APPENDICITIS; CHOLECYSTITIS; PERITONITIS; and after LIVER TRANSPLANTATION.Hepatic Veins: Veins which drain the liver.Fetus: The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after CONCEPTION until BIRTH, as distinguished from the earlier EMBRYO, MAMMALIAN.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Benzo(a)pyrene: A potent mutagen and carcinogen. It is a public health concern because of its possible effects on industrial workers, as an environmental pollutant, an as a component of tobacco smoke.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Metyrapone: An inhibitor of the enzyme STEROID 11-BETA-MONOOXYGENASE. It is used as a test of the feedback hypothalamic-pituitary mechanism in the diagnosis of CUSHING SYNDROME.Adenoma, Liver Cell: A benign epithelial tumor of the LIVER.Sterol O-Acyltransferase: An enzyme that catalyzes the formation of cholesterol esters by the direct transfer of the fatty acid group from a fatty acyl CoA derivative. This enzyme has been found in the adrenal gland, gonads, liver, intestinal mucosa, and aorta of many mammalian species. EC 2.3.1.26.Glucose-6-Phosphate: An ester of glucose with phosphoric acid, made in the course of glucose metabolism by mammalian and other cells. It is a normal constituent of resting muscle and probably is in constant equilibrium with fructose-6-phosphate. (Stedman, 26th ed)Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Ethylmorphine: A narcotic analgesic and antitussive. It is metabolized in the liver by ETHYLMORPHINE-N-DEMETHYLASE and used as an indicator of liver function.Hepatitis, Chronic: INFLAMMATION of the LIVER with ongoing hepatocellular injury for 6 months or more, characterized by NECROSIS of HEPATOCYTES and inflammatory cell (LEUKOCYTES) infiltration. Chronic hepatitis can be caused by viruses, medications, autoimmune diseases, and other unknown factors.Liver Diseases, Parasitic: Liver diseases caused by infections with PARASITES, such as tapeworms (CESTODA) and flukes (TREMATODA).Aflatoxins: Furano-furano-benzopyrans that are produced by ASPERGILLUS from STERIGMATOCYSTIN. They are structurally related to COUMARINS and easily oxidized to an epoxide form to become ALKYLATING AGENTS. Members of the group include AFLATOXIN B1; aflatoxin B2, aflatoxin G1, aflatoxin G2; AFLATOXIN M1; and aflatoxin M2.