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.

The internal portion of the kidney, consisting of striated conical masses, the renal pyramids, whose bases are adjacent to the cortex and whose apices form prominent papillae projecting into the lumen of the minor calyces.

Straight tubes commencing in the radiate part of the kidney cortex where they receive the curved ends of the distal convoluted tubules. In the medulla the collecting tubules of each pyramid converge to join a central tube (duct of Bellini) which opens on the summit of the papilla.

Phloretin is a dihydrochalcone flavonoid, primarily found in apple tree leaves and roots, which exhibits antioxidant properties and has been studied for its potential role in skin care, cancer prevention, and diabetes management, although more research is needed to fully understand its mechanisms and clinical applications.

The ability of the kidney to excrete in the urine high concentrations of solutes from the blood plasma.

Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.

A group of antigens consisting principally of Jk(a) and Jk(b), determined by allelic genes. Amorphs are encountered. Antibodies of these substances are usually weak and quite labile, stimulated by erythrocytes.

Aquaporin 2 is a water-specific channel protein that is expressed in KIDNEY COLLECTING DUCTS. The translocation of aquaporin 2 to the apical PLASMA MEMBRANE is regulated by VASOPRESSIN, and MUTATIONS in AQP2 have been implicated in a variety of kidney disorders including DIABETES INSIPIDUS.

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.

The outer zone of the KIDNEY, beneath the capsule, consisting of KIDNEY GLOMERULUS; KIDNEY TUBULES, DISTAL; and KIDNEY TUBULES, PROXIMAL.

Aquaporin 6 is an aquaglyceroporin that is found primarily in KIDNEY COLLECTING DUCTS. AQP6 protein functions as an anion-selective channel.

(11 alpha,13E,15S)-11,15-Dihydroxy-9-oxoprost-13-en-1-oic acid (PGE(1)); (5Z,11 alpha,13E,15S)-11,15-dihydroxy-9-oxoprosta-5,13-dien-1-oic acid (PGE(2)); and (5Z,11 alpha,13E,15S,17Z)-11,15-dihydroxy-9-oxoprosta-5,13,17-trien-1-oic acid (PGE(3)). Three of the six naturally occurring prostaglandins. They are considered primary in that no one is derived from another in living organisms. Originally isolated from sheep seminal fluid and vesicles, they are found in many organs and tissues and play a major role in mediating various physiological activities.

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 compounds which are substituted with one or more methyl groups.

The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.

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.

The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.

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.

Arachidonic acids are polyunsaturated fatty acids, specifically a type of omega-6 fatty acid, that are essential for human nutrition and play crucial roles in various biological processes, including inflammation, immunity, and cell signaling. They serve as precursors to eicosanoids, which are hormone-like substances that mediate a wide range of physiological responses.

The urea concentration of the blood stated in terms of nitrogen content. Serum (plasma) urea nitrogen is approximately 12% higher than blood urea nitrogen concentration because of the greater protein content of red blood cells. Increases in blood or serum urea nitrogen are referred to as azotemia and may have prerenal, renal, or postrenal causes. (From Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)

A class of porins that allow the passage of WATER and other small molecules across CELL MEMBRANES.

Devices used in a technique by which cells or tissues are grown in vitro or, by implantation, in vivo within chambers permeable to diffusion of solutes across the chamber walls. The chambers are used for studies of drug effects, osmotic responses, cytogenic and immunologic phenomena, metabolism, etc., and include tissue cages.

A photographic fixative used also in the manufacture of resins. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), this substance may reasonably be anticipated to be a carcinogen (Merck Index, 9th ed). Many of its derivatives are ANTITHYROID AGENTS and/or FREE RADICAL SCAVENGERS.

Pathological processes of the KIDNEY or its component tissues.

Transport proteins that carry specific substances in the blood or across cell membranes.

Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.

A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.

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.

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)

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.

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.

The founding member of the sodium glucose transport proteins. It is predominately expressed in the INTESTINAL MUCOSA of the SMALL INTESTINE.

A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.

Liquid by-product of excretion produced in the kidneys, temporarily stored in the bladder until discharge through the URETHRA.

The transference of a kidney from one human or animal to another.

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.

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.

The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)

Glycoproteins found on the membrane or surface of cells.

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.

The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.

A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.

Animals or humans raised in the absence of a particular disease-causing virus or other microorganism. Less frequently plants are cultivated pathogen-free.

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).

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.

Abrupt reduction in kidney function. Acute kidney injury encompasses the entire spectrum of the syndrome including acute kidney failure; ACUTE KIDNEY TUBULAR NECROSIS; and other less severe conditions.