Electrolytes: Substances that dissociate into two or more ions, to some extent, in water. Solutions of electrolytes thus conduct an electric current and can be decomposed by it (ELECTROLYSIS). (Grant & Hackh's Chemical Dictionary, 5th ed)Water-Electrolyte Imbalance: Disturbances in the body's WATER-ELECTROLYTE BALANCE.Water-Electrolyte Balance: The balance of fluid in the BODY FLUID COMPARTMENTS; total BODY WATER; BLOOD VOLUME; EXTRACELLULAR SPACE; INTRACELLULAR SPACE, maintained by processes in the body that regulate the intake and excretion of WATER and ELECTROLYTES, particularly SODIUM and POTASSIUM.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Hypernatremia: Excessive amount of sodium in the blood. (Dorland, 27th ed)Hypokalemia: Abnormally low potassium concentration in the blood. It may result from potassium loss by renal secretion or by the gastrointestinal route, as by vomiting or diarrhea. It may be manifested clinically by neuromuscular disorders ranging from weakness to paralysis, by electrocardiographic abnormalities (depression of the T wave and elevation of the U wave), by renal disease, and by gastrointestinal disorders. (Dorland, 27th ed)Hyponatremia: Deficiency of sodium in the blood; salt depletion. (Dorland, 27th ed)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.Osmolar Concentration: The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.Acid-Base Equilibrium: The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.Acid-Base Imbalance: Disturbances in the ACID-BASE EQUILIBRIUM of the body.Fluid Therapy: Therapy whose basic objective is to restore the volume and composition of the body fluids to normal with respect to WATER-ELECTROLYTE BALANCE. Fluids may be administered intravenously, orally, by intermittent gavage, or by HYPODERMOCLYSIS.Water: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Electrolysis: Destruction by passage of a galvanic electric current, as in disintegration of a chemical compound in solution.Body Water: Fluids composed mainly of water found within the body.Rehydration Solutions: Fluids restored to the body in order to maintain normal water-electrolyte balance.Jejunum: The middle portion of the SMALL INTESTINE, between DUODENUM and ILEUM. It represents about 2/5 of the remaining portion of the small intestine below duodenum.Sodium Chloride: A ubiquitous sodium salt that is commonly used to season food.Cathartics: Agents that are used to stimulate evacuation of the bowels.Intestinal Absorption: Uptake of substances through the lining of the INTESTINES.Diuresis: An increase in the excretion of URINE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Hyperkalemia: Abnormally high potassium concentration in the blood, most often due to defective renal excretion. It is characterized clinically by electrocardiographic abnormalities (elevated T waves and depressed P waves, and eventually by atrial asystole). In severe cases, weakness and flaccid paralysis may occur. (Dorland, 27th ed)Intestinal Secretions: Fluids originating from the epithelial lining of the intestines, adjoining exocrine glands and from organs such as the liver, which empty into the cavity of the intestines.Dehydration: The condition that results from excessive loss of water from a living organism.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)Isotonic Solutions: Solutions having the same osmotic pressure as blood serum, or another solution with which they are compared. (From Grant & Hackh's Chemical Dictionary, 5th ed & Dorland, 28th ed)Body Fluids: Liquid components of living organisms.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Electroplating: Coating with a metal or alloy by electrolysis.Aldosterone: A hormone secreted by the ADRENAL CORTEX that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.Electrodes: Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.Electrochemical Techniques: The utilization of an electrical current to measure, analyze, or alter chemicals or chemical reactions in solution, cells, or tissues.Diuretics: Agents that promote the excretion of urine through their effects on kidney function.Electrochemistry: The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.Drinking: The consumption of liquids.Sweat: The fluid excreted by the SWEAT GLANDS. It consists of water containing sodium chloride, phosphate, urea, ammonia, and other waste products.Solutions: The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)Ileum: The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.Blood Chemical Analysis: An examination of chemicals in the blood.Bisacodyl: A diphenylmethane stimulant laxative used for the treatment of CONSTIPATION and for bowel evacuation. (From Martindale, The Extra Pharmacopoeia, 30th ed, p871)Diarrhea: An increased liquidity or decreased consistency of FECES, such as running stool. Fecal consistency is related to the ratio of water-holding capacity of insoluble solids to total water, rather than the amount of water present. Diarrhea is not hyperdefecation or increased fecal weight.Natriuresis: Sodium excretion by URINATION.Alkalosis: A pathological condition that removes acid or adds base to the body fluids.Urine: Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the URETHRA.Secretory Rate: The amount of a substance secreted by cells or by a specific organ or organism over a given period of time; usually applies to those substances which are formed by glandular tissues and are released by them into biological fluids, e.g., secretory rate of corticosteroids by the adrenal cortex, secretory rate of gastric acid by the gastric mucosa.Thirst: A drive stemming from a physiological need for WATER.Furosemide: A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for EDEMA and chronic RENAL INSUFFICIENCY.Ions: An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.Electrophoresis, Capillary: A highly-sensitive (in the picomolar range, which is 10,000-fold more sensitive than conventional electrophoresis) and efficient technique that allows separation of PROTEINS; NUCLEIC ACIDS; and CARBOHYDRATES. (Segen, Dictionary of Modern Medicine, 1992)Colon: The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.Water Deprivation: The withholding of water in a structured experimental situation.Sodium Bicarbonate: A white, crystalline powder that is commonly used as a pH buffering agent, an electrolyte replenisher, systemic alkalizer and in topical cleansing solutions.Plasma Volume: Volume of PLASMA in the circulation. It is usually measured by INDICATOR DILUTION TECHNIQUES.Electric Power Supplies: Devices that control the supply of electric current for running electrical equipment.Pancreatic Juice: The fluid containing digestive enzymes secreted by the pancreas in response to food in the duodenum.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.Urea: A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.Inappropriate ADH Syndrome: A condition of HYPONATREMIA and renal salt loss attributed to overexpansion of BODY FLUIDS resulting from sustained release of ANTIDIURETIC HORMONES which stimulates renal resorption of water. It is characterized by normal KIDNEY function, high urine OSMOLALITY, low serum osmolality, and neurological dysfunction. Etiologies include ADH-producing neoplasms, injuries or diseases involving the HYPOTHALAMUS, the PITUITARY GLAND, and the LUNG. This syndrome can also be drug-induced.Vasopressins: Antidiuretic hormones released by the NEUROHYPOPHYSIS of all vertebrates (structure varies with species) to regulate water balance and OSMOLARITY. In general, vasopressin is a nonapeptide consisting of a six-amino-acid ring with a cysteine 1 to cysteine 6 disulfide bridge or an octapeptide containing a CYSTINE. All mammals have arginine vasopressin except the pig with a lysine at position 8. Vasopressin, a vasoconstrictor, acts on the KIDNEY COLLECTING DUCTS to increase water reabsorption, increase blood volume and blood pressure.Osmosis: Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.Ionic Liquids: Salts that melt below 100 C. Their low VOLATILIZATION can be an advantage over volatile organic solvents.Renin: A highly specific (Leu-Leu) endopeptidase that generates ANGIOTENSIN I from its precursor ANGIOTENSINOGEN, leading to a cascade of reactions which elevate BLOOD PRESSURE and increase sodium retention by the kidney in the RENIN-ANGIOTENSIN SYSTEM. The enzyme was formerly listed as EC 3.4.99.19.Potassium Deficiency: A condition due to decreased dietary intake of potassium, as in starvation or failure to administer in intravenous solutions, or to gastrointestinal loss in diarrhea, chronic laxative abuse, vomiting, gastric suction, or bowel diversion. Severe potassium deficiency may produce muscular weakness and lead to paralysis and respiratory failure. Muscular malfunction may result in hypoventilation, paralytic ileus, hypotension, muscle twitches, tetany, and rhabomyolysis. Nephropathy from potassium deficit impairs the concentrating mechanism, producing POLYURIA and decreased maximal urinary concentrating ability with secondary POLYDIPSIA. (Merck Manual, 16th ed)Refeeding Syndrome: A condition of metabolic imbalance that is caused by complications of initially feeding a severely malnourished patient too aggressively. Usually occurring within the first 5 days of refeeding, this syndrome is characterized by WATER-ELECTROLYTE IMBALANCE; GLUCOSE INTOLERANCE; CARDIAC ARRHYTHMIAS; and DIARRHEA.Saline Solution, Hypertonic: Hypertonic sodium chloride solution. A solution having an osmotic pressure greater than that of physiologic salt solution (0.9 g NaCl in 100 ml purified water).Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Mannitol: A diuretic and renal diagnostic aid related to sorbitol. It has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity.Fluids and Secretions: Liquid substances produced by living organisms to fulfill specific functions or excreted as waste.Sprue, Tropical: A chronic malabsorption syndrome, occurring mainly in residents of or visitors to the tropics or subtropics. The failed INTESTINAL ABSORPTION of nutrients from the SMALL INTESTINE results in MALNUTRITION and ANEMIA that is due to FOLIC ACID deficiency.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Glucose Solution, Hypertonic: Solution that is usually 10 percent glucose but may be higher. An isotonic solution of glucose is 5 percent.Sodium Isotopes: Stable sodium atoms that have the same atomic number as the element sodium, but differ in atomic weight. Na-23 is a stable sodium isotope.Kidney Tubules, Distal: The portion of renal tubule that begins from the enlarged segment of the ascending limb of the LOOP OF HENLE. It reenters the KIDNEY CORTEX and forms the convoluted segments of the distal tubule.Magnesium Deficiency: A nutritional condition produced by a deficiency of magnesium in the diet, characterized by anorexia, nausea, vomiting, lethargy, and weakness. Symptoms are paresthesias, muscle cramps, irritability, decreased attention span, and mental confusion, possibly requiring months to appear. Deficiency of body magnesium can exist even when serum values are normal. In addition, magnesium deficiency may be organ-selective, since certain tissues become deficient before others. (Harrison's Principles of Internal Medicine, 12th ed, p1936)Calcium Chloride: A salt used to replenish calcium levels, as an acid-producing diuretic, and as an antidote for magnesium poisoning.Inulin: A starch found in the tubers and roots of many plants. Since it is hydrolyzable to FRUCTOSE, it is classified as a fructosan. It has been used in physiologic investigation for determination of the rate of glomerular function.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.Polyuria: Urination of a large volume of urine with an increase in urinary frequency, commonly seen in diabetes (DIABETES MELLITUS; DIABETES INSIPIDUS).Pseudohypoaldosteronism: A heterogeneous group of disorders characterized by renal electrolyte transport dysfunctions. Congenital forms are rare autosomal disorders characterized by neonatal hypertension, HYPERKALEMIA, increased RENIN activity and ALDOSTERONE concentration. The Type I features HYPERKALEMIA with sodium wasting; Type II, HYPERKALEMIA without sodium wasting. Pseudohypoaldosteronism can be the result of a defective renal electrolyte transport protein or acquired after KIDNEY TRANSPLANTATION.Water Intoxication: A condition resulting from the excessive retention of water with sodium depletion.Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Chromatography, Micellar Electrokinetic Capillary: A hybrid separation technique combining both chromatographic and electrophoretic separation principles. While the method was invented to separate neutral species, it can also be applied to charged molecules such as small peptides.Potassium Chloride: A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.Secretin: A peptide hormone of about 27 amino acids from the duodenal mucosa that activates pancreatic secretion and lowers the blood sugar level. (USAN and the USP Dictionary of Drug Names, 1994, p597)Electricity: The physical effects involving the presence of electric charges at rest and in motion.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.Kidney Concentrating Ability: The ability of the kidney to excrete in the urine high concentrations of solutes from the blood plasma.Intestinal Mucosa: Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.Hematocrit: The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.Parenteral Nutrition: The administering of nutrients for assimilation and utilization by a patient who cannot maintain adequate nutrition by enteral feeding alone. Nutrients are administered by a route other than the alimentary canal (e.g., intravenously, subcutaneously).Potentiometry: Solution titration in which the end point is read from the electrode-potential variations with the concentrations of potential determining ions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Amiloride: A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)Bumetanide: A sulfamyl diuretic.Buffers: A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.Photometry: Measurement of the various properties of light.Polyethylene Glycols: Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.Bartter Syndrome: A group of disorders caused by defective salt reabsorption in the ascending LOOP OF HENLE. It is characterized by severe salt-wasting, HYPOKALEMIA; HYPERCALCIURIA; metabolic ALKALOSIS, and hyper-reninemic HYPERALDOSTERONISM without HYPERTENSION. There are several subtypes including ones due to mutations in the renal specific SODIUM-POTASSIUM-CHLORIDE SYMPORTERS.Therapeutic Irrigation: The washing of a body cavity or surface by flowing water or solution for therapy or diagnosis.Extracellular Space: Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.Natriuretic Peptides: Peptides that regulate the WATER-ELECTROLYTE BALANCE in the body, also known as natriuretic peptide hormones. Several have been sequenced (ATRIAL NATRIURETIC FACTOR; BRAIN NATRIURETIC PEPTIDE; C-TYPE NATRIURETIC PEPTIDE).Arginine Vasopressin: The predominant form of mammalian antidiuretic hormone. It is a nonapeptide containing an ARGININE at residue 8 and two disulfide-linked cysteines at residues of 1 and 6. Arg-vasopressin is used to treat DIABETES INSIPIDUS or to improve vasomotor tone and BLOOD PRESSURE.Acidosis: A pathologic condition of acid accumulation or depletion of base in the body. The two main types are RESPIRATORY ACIDOSIS and metabolic acidosis, due to metabolic acid build up.Hypocalcemia: Reduction of the blood calcium below normal. Manifestations include hyperactive deep tendon reflexes, Chvostek's sign, muscle and abdominal cramps, and carpopedal spasm. (Dorland, 27th ed)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)Electron Probe Microanalysis: Identification and measurement of ELEMENTS and their location based on the fact that X-RAYS emitted by an element excited by an electron beam have a wavelength characteristic of that element and an intensity related to its concentration. It is performed with an electron microscope fitted with an x-ray spectrometer, in scanning or transmission mode.Potassium Isotopes: Stable potassium atoms that have the same atomic number as the element potassium, but differ in atomic weight. K-41 is a stable potassium isotope.Salts: Substances produced from the reaction between acids and bases; compounds consisting of a metal (positive) and nonmetal (negative) radical. (Grant & Hackh's Chemical Dictionary, 5th ed)Spironolactone: A potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. It is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. Its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. (From Martindale, The Extra Pharmacopoeia, 30th ed, p827)Triamterene: A pteridinetriamine compound that inhibits SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS.Transistors, Electronic: Electrical devices that are composed of semiconductor material, with at least three connections to an external electronic circuit. They are used to amplify electrical signals, detect signals, or as switches.Urination: Discharge of URINE, liquid waste processed by the KIDNEY, from the body.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Enema: A solution or compound that is introduced into the RECTUM with the purpose of cleansing the COLON or for diagnostic procedures.Hypophosphatemia: A condition of an abnormally low level of PHOSPHATES in the blood.Absorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Ion-Selective Electrodes: Electrodes which can be used to measure the concentration of particular ions in cells, tissues, or solutions.Atrial Natriuretic Factor: A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight PEPTIDES derived from a common precursor and secreted mainly by the HEART ATRIUM. All these peptides share a sequence of about 20 AMINO ACIDS.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.