Organic Anion Transporters, Sodium-Independent: A subclass of ORGANIC ANION TRANSPORTERS that do not rely directly or indirectly upon sodium ion gradients for the transport of organic ions.Organic Anion Transporters: Proteins involved in the transport of organic anions. They play an important role in the elimination of a variety of endogenous substances, xenobiotics and their metabolites from the body.Organic Anion Transport Protein 1: A polyspecific transporter for organic cations found primarily in the kidney. It mediates the coupled exchange of alpha-ketoglutarate with organic ions such as P-AMINOHIPPURIC ACID.p-Aminohippuric Acid: The glycine amide of 4-aminobenzoic acid. Its sodium salt is used as a diagnostic aid to measure effective renal plasma flow (ERPF) and excretory capacity.Anion Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of negatively charged molecules (anions) across a biological membrane.Anions: Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.Probenecid: The prototypical uricosuric agent. It inhibits the renal excretion of organic anions and reduces tubular reabsorption of urate. Probenecid has also been used to treat patients with renal impairment, and, because it reduces the renal tubular excretion of other drugs, has been used as an adjunct to antibacterial therapy.Organic Anion Transporters, Sodium-Dependent: A subclass of ORGANIC ANION TRANSPORTERS whose transport of organic anions is driven either directly or indirectly by a gradient of sodium ions.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.Uricosuric Agents: Gout suppressants that act directly on the renal tubule to increase the excretion of uric acid, thus reducing its concentrations in plasma.Organic Anion Transport Polypeptide C: An organic anion transporter found in human liver. It is capable of transporting a variety organic anions and mediates sodium-independent uptake of bile in the liver.Estrone: An aromatized C18 steroid with a 3-hydroxyl group and a 17-ketone, a major mammalian estrogen. It is converted from ANDROSTENEDIONE directly, or from TESTOSTERONE via ESTRADIOL. In humans, it is produced primarily by the cyclic ovaries, PLACENTA, and the ADIPOSE TISSUE of men and postmenopausal women.Sulfobromophthalein: A phenolphthalein that is used as a diagnostic aid in hepatic function determination.Symporters: Membrane transporters that co-transport two or more dissimilar molecules in the same direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.Organic Cation Transport Proteins: A family of proteins involved in the transport of organic cations. They play an important role in the elimination of a variety of endogenous substances, xenobiotics, and their metabolites from the body.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Ochratoxins: Isocoumarins found in ASPERGILLUS OCHRACEUS and other FUNGI. Ochratoxin contaminated FOOD has been responsible for cases of FOODBORNE DISEASES.Taurocholic Acid: The product of conjugation of cholic acid with taurine. Its sodium salt is the chief ingredient of the bile of carnivorous animals. It acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as a cholagogue and cholerectic.Multidrug Resistance-Associated Proteins: A sequence-related subfamily of ATP-BINDING CASSETTE TRANSPORTERS that actively transport organic substrates. Although considered organic anion transporters, a subset of proteins in this family have also been shown to convey drug resistance to neutral organic drugs. Their cellular function may have clinical significance for CHEMOTHERAPY in that they transport a variety of ANTINEOPLASTIC AGENTS. Overexpression of proteins in this class by NEOPLASMS is considered a possible mechanism in the development of multidrug resistance (DRUG RESISTANCE, MULTIPLE). Although similar in function to P-GLYCOPROTEINS, the proteins in this class share little sequence homology to the p-glycoprotein family of proteins.Organic Anion Transporters, ATP-Dependent: A subclass of ORGANIC ANION TRANSPORTERS whose transport of organic anions is linked directly to the hydrolysis of ATP. The subclass includes those ATP-BINDING CASSETTE TRANSPORTERS that transport organic ions.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.ATP-Binding Cassette Transporters: A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.Kidney Tubules, Proximal: The renal tubule portion that extends from the BOWMAN CAPSULE in the KIDNEY CORTEX into the KIDNEY MEDULLA. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the U-shaped LOOP OF HENLE.Membrane Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.GlutaratesDicarboxylic Acid Transporters: A family of organic anion transporters that specifically transport DICARBOXYLIC ACIDS such as alpha-ketoglutaric acid across cellular membranes.Dicarboxylic AcidsXenopus laevis: The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.Sodium-Phosphate Cotransporter Proteins, Type I: A family of sodium-phosphate cotransporter proteins that also transport organic ANIONS. They are low affinity phosphate transporters.Sodium-Coupled Vitamin C Transporters: Membrane transport proteins that actively co-transport ASCORBIC ACID and sodium ions across the CELL MEMBRANE. Dietary absorption of VITAMIN C is highly dependent upon this class of transporters and a subset of SODIUM GLUCOSE TRANSPORTERS which transport the oxidized form of vitamin C, DEHYDROASCORBIC ACID.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.RNA, Complementary: Synthetic transcripts of a specific DNA molecule or fragment, made by an in vitro transcription system. This cRNA can be labeled with radioactive uracil and then used as a probe. (King & Stansfield, A Dictionary of Genetics, 4th ed)Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Oocytes: Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).Unithiol: A chelating agent used as an antidote to heavy metal poisoning.Bile Canaliculi: Minute intercellular channels that occur between liver cells and carry bile towards interlobar bile ducts. Also called bile capillaries.Phenolsulfonphthalein: Red dye, pH indicator, and diagnostic aid for determination of renal function. It is used also for studies of the gastrointestinal and other systems.Choroid Plexus: A villous structure of tangled masses of BLOOD VESSELS contained within the third, lateral, and fourth ventricles of the BRAIN. It regulates part of the production and composition of CEREBROSPINAL FLUID.Renal Agents: Drugs used for their effects on the kidneys' regulation of body fluid composition and volume. The most commonly used are the diuretics. Also included are drugs used for their antidiuretic and uricosuric actions, for their effects on the kidneys' clearance of other drugs, and for diagnosis of renal function.Organic Cation Transporter 1: An organic cation transporter found in kidney. It is localized to the basal lateral membrane and is likely to be involved in the renal secretion of organic cations.Leukotriene C4: The conjugation product of LEUKOTRIENE A4 and glutathione. It is the major arachidonic acid metabolite in macrophages and human mast cells as well as in antigen-sensitized lung tissue. It stimulates mucus secretion in the lung, and produces contractions of nonvascular and some VASCULAR SMOOTH MUSCLE. (From Dictionary of Prostaglandins and Related Compounds, 1990)Kinetics: The rate dynamics in chemical or physical systems.Hyperbilirubinemia, Hereditary: Inborn errors of bilirubin metabolism resulting in excessive amounts of bilirubin in the circulating blood, either because of increased bilirubin production or because of delayed clearance of bilirubin from the blood.LLC-PK1 Cells: Epithelial cell line originally derived from porcine kidneys. It is used for pharmacologic and metabolic studies.Indican: A substance occurring in the urine of mammals and also in blood plasma as the normal metabolite of tryptophan. An increased urinary excretion of indican is seen in Hartnup disease from the bacterial degradation of unabsorbed tryptophan.Penicillin G: A penicillin derivative commonly used in the form of its sodium or potassium salts in the treatment of a variety of infections. It is effective against most gram-positive bacteria and against gram-negative cocci. It has also been used as an experimental convulsant because of its actions on GAMMA-AMINOBUTYRIC ACID mediated synaptic transmission.Hyperbilirubinemia: A condition characterized by an abnormal increase of BILIRUBIN in the blood, which may result in JAUNDICE. Bilirubin, a breakdown product of HEME, is normally excreted in the BILE or further catabolized before excretion in the urine.2,4-Dichlorophenoxyacetic Acid: An herbicide with irritant effects on the eye and the gastrointestinal system.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.Sulfinpyrazone: A uricosuric drug that is used to reduce the serum urate levels in gout therapy. It lacks anti-inflammatory, analgesic, and diuretic properties.Iodopyracet: An ionic monomeric contrast medium that was formerly used for a variety of diagnostic procedures. (From Martindale, The Extra Pharmacopoeia, 30th ed, p706)Catecholamine Plasma Membrane Transport Proteins: A group of membrane transport proteins that transport biogenic amine derivatives of catechol across the PLASMA MEMBRANE. Catecholamine plasma membrane transporter proteins regulate neural transmission as well as catecholamine metabolism and recycling.Ion Transport: The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.Sodium-Phosphate Cotransporter Proteins, Type III: A family of highly conserved and widely expressed sodium-phosphate cotransporter proteins. They are electrogenic sodium-dependent transporters of phosphate that were originally identified as retroviral receptors in HUMANS and have been described in yeast and many other organisms.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Sodium-Phosphate Cotransporter Proteins: A family of symporters that facilitate sodium-dependent membrane transport of phosphate.Cefotiam: One of the CEPHALOSPORINS that has a broad spectrum of activity against both gram-positive and gram-negative microorganisms.Flounder: Common name for two families of FLATFISHES belonging to the order Pleuronectiformes: left-eye flounders (Bothidae) and right-eye flounders (Pleuronectidae). The latter is more commonly used in research.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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.Jaundice, Chronic Idiopathic: A benign, autosomally recessive inherited hyperbilirubinemia characterized by the presence of a dark pigment in the centrilobular region of the liver cells. There is a functional defect in biliary excretion of bilirubin, cholephilic dyes, and porphyrins. Affected persons may be asymptomatic or have vague constitutional or gastrointestinal symptoms. The liver may be slightly enlarged, and oral and intravenous cholangiography fails to visualize the biliary tract.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.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.Methotrexate: An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of TETRAHYDROFOLATE DEHYDROGENASE and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA.Mercury Isotopes: Stable mercury atoms that have the same atomic number as the element mercury, but differ in atomic weight. Hg-196, 198-201, and 204 are stable mercury isotopes.Cimetidine: A histamine congener, it competitively inhibits HISTAMINE binding to HISTAMINE H2 RECEPTORS. Cimetidine has a range of pharmacological actions. It inhibits GASTRIC ACID secretion, as well as PEPSIN and GASTRIN output.Rats, Mutant Strains: Rats bearing mutant genes which are phenotypically expressed in the animals.Dehydroepiandrosterone Sulfate: The circulating form of a major C19 steroid produced primarily by the ADRENAL CORTEX. DHEA sulfate serves as a precursor for TESTOSTERONE; ANDROSTENEDIONE; ESTRADIOL; and ESTRONE.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.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.Sodium-Glucose Transporter 1: The founding member of the sodium glucose transport proteins. It is predominately expressed in the INTESTINAL MUCOSA of the SMALL INTESTINE.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Biotinylation: Incorporation of biotinyl groups into molecules.Rats, Inbred LEC: A cinnamon-colored strain of Long-Evans rats which carries a mutation causing fulminant hepatitis and jaundice, with an associated gross accumulation of copper in the liver. This strain is a model for Wilson's Disease (see HEPATOLENTICULAR DEGENERATION).P-Glycoprotein: A 170-kDa transmembrane glycoprotein from the superfamily of ATP-BINDING CASSETTE TRANSPORTERS. It serves as an ATP-dependent efflux pump for a variety of chemicals, including many ANTINEOPLASTIC AGENTS. Overexpression of this glycoprotein is associated with multidrug resistance (see DRUG RESISTANCE, MULTIPLE).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.Cephaloridine: A cephalosporin antibiotic.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Kidney Cortex: The outer zone of the KIDNEY, beneath the capsule, consisting of KIDNEY GLOMERULUS; KIDNEY TUBULES, DISTAL; and KIDNEY TUBULES, PROXIMAL.Sulfuric Acid Esters: Organic esters of sulfuric acid.Pharmaceutical Preparations: Drugs intended for human or veterinary use, presented in their finished dosage form. Included here are materials used in the preparation and/or formulation of the finished dosage form.Antiporters: Membrane transporters that co-transport two or more dissimilar molecules in the opposite direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.Aminopterin: A folic acid derivative used as a rodenticide that has been shown to be teratogenic.Pravastatin: An antilipemic fungal metabolite isolated from cultures of Nocardia autotrophica. It acts as a competitive inhibitor of HMG CoA reductase (HYDROXYMETHYLGLUTARYL COA REDUCTASES).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.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Stevia: A plant genus of the family ASTERACEAE. Members contain stevioside and other sweet diterpene glycosides. The leaf is used for sweetening (SWEETENING AGENTS).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.COS Cells: CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)Sodium-Phosphate Cotransporter Proteins, Type IIb: A sodium-dependent phosphate transporter present primarily at apical sites of EPITHELIAL CELLS in the SMALL INTESTINE.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Physiological Processes: The functions and activities of living organisms that support life in single- or multi-cellular organisms from their origin through the progression of life.Uric Acid: An oxidation product, via XANTHINE OXIDASE, of oxypurines such as XANTHINE and HYPOXANTHINE. It is the final oxidation product of purine catabolism in humans and primates, whereas in most other mammals URATE OXIDASE further oxidizes it to ALLANTOIN.P-Glycoproteins: A subfamily of transmembrane proteins from the superfamily of ATP-BINDING CASSETTE TRANSPORTERS that are closely related in sequence to P-GLYCOPROTEIN. When overexpressed, they function as ATP-dependent efflux pumps able to extrude lipophilic drugs, especially ANTINEOPLASTIC AGENTS, from cells causing multidrug resistance (DRUG RESISTANCE, MULTIPLE). Although P-Glycoproteins share functional similarities to MULTIDRUG RESISTANCE-ASSOCIATED PROTEINS they are two distinct subclasses of ATP-BINDING CASSETTE TRANSPORTERS, and have little sequence homology.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.Microvilli: Minute projections of cell membranes which greatly increase the surface area of the cell.Liddle Syndrome: Familial pseudoaldosteronism characterized by autosomal dominant inheritance of hypertension with HYPOKALEMIA; ALKALOSIS; RENIN and ALDOSTERONE level decreases. It is caused by mutations in EPITHELIAL SODIUM CHANNELS beta and gamma subunits. Different mutations in the same EPITHELIAL SODIUM CHANNELS subunits can cause PSEUDOHYPOALDOSTERONISM, TYPE I, AUTOSOMAL DOMINANT.Amino Acid Transport System X-AG: A family of POTASSIUM and SODIUM-dependent acidic amino acid transporters that demonstrate a high affinity for GLUTAMIC ACID and ASPARTIC ACID. Several variants of this system are found in neuronal tissue.XanthurenatesHepatocytes: The main structural component of the LIVER. They are specialized EPITHELIAL CELLS that are organized into interconnected plates called lobules.Monosaccharide Transport Proteins: A large group of membrane transport proteins that shuttle MONOSACCHARIDES across CELL MEMBRANES.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)Salicylates: The salts or esters of salicylic acids, or salicylate esters of an organic acid. Some of these have analgesic, antipyretic, and anti-inflammatory activities by inhibiting prostaglandin synthesis.Ketoglutaric Acids: A family of compounds containing an oxo group with the general structure of 1,5-pentanedioic acid. (From Lehninger, Principles of Biochemistry, 1982, p442)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.Propionates: Derivatives of propionic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxyethane structure.Sodium-Phosphate Cotransporter Proteins, Type IIa: An electrogenic sodium-dependent phosphate transporter. It is present primarily in BRUSH BORDER membranes of PROXIMAL RENAL TUBULES.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Blood-Brain Barrier: Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.TritiumDrug Resistance, Multiple: Simultaneous resistance to several structurally and functionally distinct drugs.Cyclic P-OxidesXenobiotics: Chemical substances that are foreign to the biological system. They include naturally occurring compounds, drugs, environmental agents, carcinogens, insecticides, etc.Furosemide: A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for EDEMA and chronic RENAL INSUFFICIENCY.Biliary Tract: The BILE DUCTS and the GALLBLADDER.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Adenosine Triphosphate: An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.Xenopus: An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.Anion Exchange Protein 1, Erythrocyte: A major integral transmembrane protein of the ERYTHROCYTE MEMBRANE. It is the anion exchanger responsible for electroneutral transporting in CHLORIDE IONS in exchange of BICARBONATE IONS allowing CO2 uptake and transport from tissues to lungs by the red blood cells. Genetic mutations that result in a loss of the protein function have been associated with type 4 HEREDITARY SPHEROCYTOSIS.Blotting, 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.Pharmacokinetics: Dynamic and kinetic mechanisms of exogenous chemical and DRUG LIBERATION; ABSORPTION; BIOLOGICAL TRANSPORT; TISSUE DISTRIBUTION; BIOTRANSFORMATION; elimination; and DRUG TOXICITY as a function of dosage, and rate of METABOLISM. LADMER, ADME and ADMET are abbreviations for liberation, absorption, distribution, metabolism, elimination, and toxicology.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Phosphates: Inorganic salts of phosphoric acid.Glucose Transporter Type 1: A ubiquitously expressed glucose transporter that is important for constitutive, basal GLUCOSE transport. It is predominately expressed in ENDOTHELIAL CELLS and ERYTHROCYTES at the BLOOD-BRAIN BARRIER and is responsible for GLUCOSE entry into the BRAIN.CHO Cells: CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.Kidney Tubules: Long convoluted tubules in the nephrons. They collect filtrate from blood passing through the KIDNEY GLOMERULUS and process this filtrate into URINE. Each renal tubule consists of a BOWMAN CAPSULE; PROXIMAL KIDNEY TUBULE; LOOP OF HENLE; DISTAL KIDNEY TUBULE; and KIDNEY COLLECTING DUCT leading to the central cavity of the kidney (KIDNEY PELVIS) that connects to the URETER.Excitatory Amino Acid Transporter 3: A neuronal and epithelial type glutamate plasma membrane transporter protein.Excitatory Amino Acid Transporter 2: A glutamate plasma membrane transporter protein found in ASTROCYTES and in the LIVER.Caco-2 Cells: Human colonic ADENOCARCINOMA cells that are able to express differentiation features characteristic of mature intestinal cells, such as ENTEROCYTES. These cells are valuable in vitro tools for studies related to intestinal cell function and differentiation.GABA Plasma Membrane Transport Proteins: A family of plasma membrane neurotransmitter transporter proteins that regulates extracellular levels of the inhibitory neurotransmitter GAMMA-AMINOBUTYRIC ACID. They differ from GABA RECEPTORS, which signal cellular responses to GAMMA-AMINOBUTYRIC ACID. They control GABA reuptake into PRESYNAPTIC TERMINALS in the CENTRAL NERVOUS SYSTEM through high-affinity sodium-dependent transport.Opossums: New World marsupials of the family Didelphidae. Opossums are omnivorous, largely nocturnal and arboreal MAMMALS, grow to about three feet in length, including the scaly prehensile tail, and have an abdominal pouch in which the young are carried at birth.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.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.Glutamate Plasma Membrane Transport Proteins: A family of plasma membrane neurotransmitter transporter proteins that couple the uptake of GLUTAMATE with the import of SODIUM ions and PROTONS and the export of POTASSIUM ions. In the CENTRAL NERVOUS SYSTEM they regulate neurotransmission through synaptic reuptake of the excitatory neurotransmitter glutamate. Outside the central nervous system they function as signal mediators and regulators of glutamate metabolism.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Toxins, Biological: Specific, characterizable, poisonous chemicals, often PROTEINS, with specific biological properties, including immunogenicity, produced by microbes, higher plants (PLANTS, TOXIC), or ANIMALS.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Sodium-Glucose Transport Proteins: Monosaccharide transport proteins that function as active symporters. They utilize SODIUM or HYDROGEN IONS to transport GLUCOSE across CELL MEMBRANES.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.PhlorhizinMonocarboxylic Acid Transporters: A family of proteins involved in the transport of monocarboxylic acids such as LACTIC ACID and PYRUVIC ACID across cellular membranes.Cercopithecus aethiops: A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Sulfates: Inorganic salts of sulfuric acid.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)Recombinant Proteins: Proteins prepared by recombinant DNA technology.Bicarbonates: Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.Cholestasis: Impairment of bile flow due to obstruction in small bile ducts (INTRAHEPATIC CHOLESTASIS) or obstruction in large bile ducts (EXTRAHEPATIC CHOLESTASIS).Sodium-Phosphate Cotransporter Proteins, Type IIc: A non-electrogenic sodium-dependent phosphate transporter. It is found primarily in apical membranes of PROXIMAL RENAL TUBULES.Organophosphonates: Carbon-containing phosphonic acid compounds. Included under this heading are compounds that have carbon bound to either OXYGEN atom or the PHOSPHOROUS atom of the (P=O)O2 structure.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.HEK293 Cells: A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.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.Folic Acid Antagonists: Inhibitors of the enzyme, dihydrofolate reductase (TETRAHYDROFOLATE DEHYDROGENASE), which converts dihydrofolate (FH2) to tetrahydrofolate (FH4). They are frequently used in cancer chemotherapy. (From AMA, Drug Evaluations Annual, 1994, p2033)Bilirubin: A bile pigment that is a degradation product of HEME.Chloride-Bicarbonate Antiporters: Electroneutral chloride bicarbonate exchangers that allow the exchange of BICARBONATE IONS exchange for CHLORIDE IONS across the cellular membrane. The action of specific antiporters in this class serve important functions such as allowing the efficient exchange of bicarbonate across red blood cell membranes as they passage through capillaries and the reabsorption of bicarbonate ions by the kidney.Serotonin Plasma Membrane Transport Proteins: Sodium chloride-dependent neurotransmitter symporters located primarily on the PLASMA MEMBRANE of serotonergic neurons. They are different than SEROTONIN RECEPTORS, which signal cellular responses to SEROTONIN. They remove SEROTONIN from the EXTRACELLULAR SPACE by high affinity reuptake into PRESYNAPTIC TERMINALS. Regulates signal amplitude and duration at serotonergic synapses and is the site of action of the SEROTONIN UPTAKE INHIBITORS.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Amino Acid Transport Systems: Cellular proteins and protein complexes that transport amino acids across biological membranes.Formycins: Pyrazolopyrimidine ribonucleosides isolated from Nocardia interforma. They are antineoplastic antibiotics with cytostatic properties.Hepatocyte Nuclear Factor 1-alpha: Hepatocyte nuclear factor 1-alpha is a transcription factor found in the LIVER; PANCREAS; and KIDNEY that regulates HOMEOSTASIS of GLUCOSE.4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid: An inhibitor of anion conductance including band 3-mediated anion transport.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.Dopamine Plasma Membrane Transport Proteins: Sodium chloride-dependent neurotransmitter symporters located primarily on the PLASMA MEMBRANE of dopaminergic neurons. They remove DOPAMINE from the EXTRACELLULAR SPACE by high affinity reuptake into PRESYNAPTIC TERMINALS and are the target of DOPAMINE UPTAKE INHIBITORS.Histamine H2 Antagonists: Drugs that selectively bind to but do not activate histamine H2 receptors, thereby blocking the actions of histamine. Their clinically most important action is the inhibition of acid secretion in the treatment of gastrointestinal ulcers. Smooth muscle may also be affected. Some drugs in this class have strong effects in the central nervous system, but these actions are not well understood.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Adenine: A purine base and a fundamental unit of ADENINE NUCLEOTIDES.Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Mercury: A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.Amino Acid Transport System ASC: A ubiquitous sodium-dependent neutral amino acid transporter. The preferred substrates for this transporter system include ALANINE; SERINE; and CYSTEINE.Cricetulus: A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Phosphate-Binding Proteins: Proteins that bind to and are involved in the metabolism of phosphate ions.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Diuretics: Agents that promote the excretion of urine through their effects on kidney function.QuinolinesRabbits: 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.Killifishes: Small oviparous fishes in the family Cyprinodontidae, usually striped or barred black. They are much used in mosquito control.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.Epithelial Cells: Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.Phosphate Transport Proteins: Membrane proteins that are involved in the active transport of phosphate.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Nucleoside Transport Proteins: Proteins involved in the transport of NUCLEOSIDES across cellular membranes.Glucose Transporter Type 2: A glucose transport facilitator that is expressed primarily in PANCREATIC BETA CELLS; LIVER; and KIDNEYS. It may function as a GLUCOSE sensor to regulate INSULIN release and glucose HOMEOSTASIS.Glucose Transporter Type 5: A hexose transporter that mediates FRUCTOSE transport in SKELETAL MUSCLE and ADIPOCYTES and is responsible for luminal uptake of dietary fructose in the SMALL INTESTINE.Microinjections: The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.Excitatory Amino Acid Transporter 1: A glial type glutamate plasma membrane transporter protein found predominately in ASTROCYTES. It is also expressed in HEART and SKELETAL MUSCLE and in the PLACENTA.Isoquinolines: A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)Hemicholinium 3: A potent inhibitor of the high affinity uptake system for CHOLINE. It has less effect on the low affinity uptake system. Since choline is one of the components of ACETYLCHOLINE, treatment with hemicholinium can deplete acetylcholine from cholinergic terminals. Hemicholinium 3 is commonly used as a research tool in animal and in vitro experiments.Glutamic Acid: A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.Sodium-Phosphate Cotransporter Proteins, Type II: A family of sodium-phosphate cotransporter proteins with eight transmembrane domains. They are present primarily in the KIDNEY and SMALL INTESTINE and are responsible for renal and small intestinal epithelial transport of phosphate.Benzbromarone: Uricosuric that acts by increasing uric acid clearance. It is used in the treatment of gout.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Mice, Inbred C57BL