Biomaterial Database

Intracellular cystine loading inhibits transport in the rabbit proximal convoluted tubule. 1990

R F Salmon, and M Baum

Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235.

Cystinosis is an autosomal recessive disorder characterized by a high intracellular cystine concentration. To establish an in vitro model of this disorder and examine the mechanism of the proximal tubule transport defect seen with elevated intracellular cystine concentrations, rabbit proximal convoluted tubules (PCT) were perfused in vitro. PCTs were loaded with cystine using cystine dimethyl ester, a permeative methyl ester derivative. Bath cystine dimethyl ester (0.5 mM) reduced volume absorption (Jv) (0.67 +/- 0.07 to 0.15 +/- 0.09 nl/mm.min, P less than 0.01), bicarbonate transport (JTCO2) (47.2 +/- 4.9 to 11.1 +/- 2.8 pmol/mm.min, P less than 0.001) and glucose transport (JGLU) (34.1 +/- 1.5 to 19.7 +/- 1.5 pmol/mm.min, P less than 0.001). The methyl esters of leucine (0.5 mM), and tryptophan (0.5 and 2.0 mM) had no effect on these parameters. To examine if intracellular reduction of cystine to cysteine could contribute to the inhibition in transport, the effect of bath cysteine methyl ester on proximal tubular transport was examined. Bath cysteine methyl ester (2 but not 0.5 mM) resulted in an inhibition in Jv, JGLU, and JTCO2. Cystine dimethyl ester had no effect on mannitol or bicarbonate permeability. These data are consistent with intracellular proximal tubular cystine accumulation resulting in an inhibition of active transport.

UI	MeSH Term	Description	Entries
D007687	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.	Proximal Kidney Tubule,Proximal Renal Tubule,Kidney Tubule, Proximal,Proximal Kidney Tubules,Proximal Renal Tubules,Renal Tubule, Proximal,Renal Tubules, Proximal,Tubule, Proximal Kidney,Tubule, Proximal Renal,Tubules, Proximal Kidney,Tubules, Proximal Renal
D007930	Leucine	An essential branched-chain amino acid important for hemoglobin formation.	L-Leucine,Leucine, L-Isomer,L-Isomer Leucine,Leucine, L Isomer
D010477	Perfusion	Treatment process involving the injection of fluid into an organ or tissue.	Perfusions
D010539	Permeability	Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.	Permeabilities
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D003553	Cystine	A covalently linked dimeric nonessential amino acid formed by the oxidation of CYSTEINE. Two molecules of cysteine are joined together by a disulfide bridge to form cystine.	Copper Cystinate,L-Cystine,L Cystine
D003554	Cystinosis	A metabolic disease characterized by the defective transport of CYSTINE across the lysosomal membrane due to mutation of a membrane protein cystinosin. This results in cystine accumulation and crystallization in the cells causing widespread tissue damage. In the KIDNEY, nephropathic cystinosis is a common cause of RENAL FANCONI SYNDROME.	Cystine Diathesis,Cystine Disease,Cystine Storage Disease,Cystinoses,Cystinosin, Defect of,Cystinosis, Nephropathic,Lysosomal Cystine Transport Protein, Defect Of,Nephropathic Cystinosis,Cystine Diatheses,Cystine Diseases,Cystine Storage Diseases,Cystinoses, Nephropathic,Defect of Cystinosin,Diatheses, Cystine,Diathesis, Cystine,Nephropathic Cystinoses,Storage Disease, Cystine,Storage Diseases, Cystine
D005198	Fanconi Syndrome	A hereditary or acquired form of generalized dysfunction of the PROXIMAL KIDNEY TUBULE without primary involvement of the KIDNEY GLOMERULUS. It is usually characterized by the tubular wasting of nutrients and salts (GLUCOSE; AMINO ACIDS; PHOSPHATES; and BICARBONATES) resulting in HYPOKALEMIA; ACIDOSIS; HYPERCALCIURIA; and PROTEINURIA.	De Toni-Debre-Fanconi Syndrome,Lignac-Fanconi Syndrome,Proximal Renal Tubular Dysfunction,Renal Fanconi Syndrome,Adult Fanconi Syndrome,Fanconi Bickel Syndrome,Fanconi Renotubular Syndrome,Fanconi Syndrome with Intestinal Malabsorption and Galactose Intolerance,Fanconi Syndrome without Cystinosis,Fanconi-Bickel Syndrome,Glycogen Storage Disease XI,Glycogenosis, Fanconi Type,Hepatic Glycogenosis with Amino Aciduria and Glucosuria,Hepatic Glycogenosis with Fanconi Nephropathy,Hepatorenal Glycogenosis with Renal Fanconi Syndrome,Idiopathic De Toni-Debre-Fanconi Syndrome,Luder-Sheldon Syndrome,Neonatal De Toni-Debre-Fanconi Syndrome,Primary Toni-Debre-Fanconi Syndrome,Pseudo-Phlorizin Diabetes,Toni-Debre-Fanconi Syndrome,Bickel Syndrome, Fanconi,Diabete, Pseudo-Phlorizin,Diabetes, Pseudo-Phlorizin,Fanconi Syndrome, Adult,Fanconi Syndrome, Renal,Fanconi Type Glycogenosis,Fanconi-Bickel Syndromes,Lignac Fanconi Syndrome,Luder Sheldon Syndrome,Pseudo Phlorizin Diabetes,Pseudo-Phlorizin Diabete,Renotubular Syndrome, Fanconi,Syndrome, Adult Fanconi,Syndrome, Fanconi,Syndrome, Fanconi Bickel,Syndrome, Fanconi Renotubular,Syndrome, Fanconi-Bickel,Syndrome, Lignac-Fanconi,Syndrome, Luder-Sheldon,Syndrome, Renal Fanconi,Syndromes, Fanconi-Bickel
D005260	Female		Females
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