Biomaterial Database

Juxtamedullary and superficial nephron phosphate reabsorption in the cat. 1980

S Goldfarb

The cat kidney possesses discrete venous drainage systems for superficial and deep (juxtamedullary) portions of the renal cortex. Arteriovenous (A-V) extraction and micropuncture studies may thus be used to evaluate PO4 transport in the two nephron populations. Determinations of A-V extraction showed whole kidney percentage of fractional PO4 excretion (%FEPO4) was 29.04 +/- 2.01%, percentage of fractional delivery of PO4 (%FDPO4) from the superficial nephrons was 42.94 +/- 2.42%, and that from deep nephrons was 22.35 +/- 2.05%. The %FDPO4 from superficial nephrons was significantly greater than %FEPO, in urine (P < 0.001) and than %FDPO4 from deep nephrons (P < 0.001). Micropuncture studies showed %FDPO4 from late distal tubules was 41.63 +/- 3.61%, while %FEPO4 in urine was 30.24 +/- 2.22%. Infusion of acetazolamide increased both %FEPO4 in urine and %FDPO4 from deep nephrons (A-V extraction studies), but had no effect on %FDPO4 from either superficial nephrons (A-V extraction) or from late distal tubules (micropuncture), thus abolishing the differences between superficial and deep compartments. Nephron heterogeneity apparently exists for superficial and juxtamedullary PO4 reabsorption in the cat. Acetazolamide increase %FEPO4 in urine primarily by reducing deep nephron PO4 reabsorption.

UI	MeSH Term	Description	Entries
D007606	Juxtaglomerular Apparatus	A complex of cells consisting of juxtaglomerular cells, extraglomerular mesangium lacis cells, the macula densa of the distal convoluted tubule, and granular epithelial peripolar cells. Juxtaglomerular cells are modified SMOOTH MUSCLE CELLS found in the walls of afferent glomerular arterioles and sometimes the efferent arterioles. Extraglomerular mesangium lacis cells are located in the angle between the afferent and efferent glomerular arterioles. Granular epithelial peripolar cells are located at the angle of reflection of the parietal to visceral angle of the renal corpuscle.	Apparatus, Juxtaglomerular
D007684	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.	Kidney Tubule,Tubule, Kidney,Tubules, Kidney
D008297	Male		Males
D009399	Nephrons	The functional units of the kidney, consisting of the glomerulus and the attached tubule.	Nephron
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D002118	Calcium	A basic element found in nearly all 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.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D005260	Female		Females
D000086	Acetazolamide	One of the CARBONIC ANHYDRASE INHIBITORS that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. (From Smith and Reynard, Textbook of Pharmacology, 1991, p337)	Acetadiazol,Acetazolam,Acetazolamide Sodium, (Sterile),Acetazolamide, Monosodium Salt,Ak-Zol,Apo-Acetazolamide,Diacarb,Diamox,Diuramide,Défiltran,Edemox,Glauconox,Glaupax,Huma-Zolamide,Ak Zol,AkZol,Apo Acetazolamide,ApoAcetazolamide,Huma Zolamide,HumaZolamide
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia