scholarly journals Separate Transport Systems for Sugars and Amino Acids in Developing Rat Kidney Cortex

1971 ◽  
Vol 68 (2) ◽  
pp. 372-376 ◽  
Author(s):  
S. Segal ◽  
C. Rea ◽  
I. Smith
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Transport Systems ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Developing Rat

Effect on kidney S35O4 uptake of compounds related to SO4 transport and metabolism

1964 ◽  
Vol 207 (1) ◽  
pp. 84-88 ◽  
Author(s):  
Ingrith J. Deyrup
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Point Of View ◽  
Transport Systems ◽  
Kidney Cortex ◽  
Cellular Transport ◽  
Rat Kidney Cortex ◽  
Aryl Sulfatase

Experiments have been carried out to test the effects on S35O4 accumulation by rat kidney cortex slices in vitro of 1) compounds known to affect renal SO4 reabsorption (thiosulfate, amino acids); 2) compounds secreted by the kidney, or known to affect specific cellular transport systems (including tetraethylammonium ions, guanidine, creatinine, carinamide, probenecid, phloretin, diethylstilbestrol, ethylenediaminetetraacetate sodium); and 3) compounds related to SO4 metabolism (aryl sulfatase substrates). Under the conditions of the experiment, net S35O4 uptake was depressed by thiosulfate, certain amino acids, carinamide, phloretin, diethylstilbestrol, and aryl sulfatase substrates. It was enhanced by ethylenediaminetetraacetate sodium. Other compounds were without effect. These results are discussed from the point of view of the possible relationship between SO4 accumulation in vitro and transport in vivo.

Transport of amino acids by slices of rat-kidney cortex

1961 ◽  
Vol 54 (3) ◽  
pp. 479-488 ◽  
Author(s):  
Leon E. Rosenberg ◽  
Alberta Blair ◽  
Stanton Segal
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex

scholarly journals Inhibition of cellular transport processes by 5-thio-d-glucopyranose

1972 ◽  
Vol 130 (4) ◽  
pp. 919-925 ◽  
Author(s):  
Roy L. Whistler ◽  
William C. Lake
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Transport Processes ◽  
Diaphragm Muscle ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Facilitated Diffusion ◽  
Cellular Transport ◽  
Rat Kidney Cortex ◽  
Diffusion Transport

5-Thio-d-glucopyranose, the nearest analogue of normal d-glucose, which is proving a useful tool in examinations of d-glucose biochemistry, affects active and facilitated-diffusion transport processes. 5-Thio-d-glucose is readily transported in rabbit kidney-cortex slices and reaches a tissue/medium ratio of 6.5 within 40min. The sulphur analogue shows typical saturation kinetics with a Km value of 2.4mm and Vmax. value of 70μmol/h per g of cell water. Uptake of 5-thio-d-glucose is phlorrhizin-sensitive, Na+-dependent and energy-dependent. d-Galactose and methyl α-d-glucopyranoside transport is competitively inhibited by 5-thio-d-glucose with Ki values of 4.8 and 9.7mm respectively. 5-Thio-d-glucose thus shows all of the characteristics of active transport in kidney cortex. Transport of neutral amino acids in rat kidney cortex is inhibited by 5-thio-d-glucose. Thus 5.6mm-5-thio-d-glucose causes a 25–30% inhibition of the transport of glycine and the non-metabolized amino acids cycloleucine and α-aminoisobutyric acid. 5-Thio-d-glucose is freely taken up by the facilitated-diffusion transport system in rat diaphragm muscle. The sulphur analogue inhibits the transport of d-xylose in this tissue but has no effect on the uptake of d-arabinose. It is concluded that the ring heteroatom is not an effector of binding in the transport processes examined and causes no important alteration in the conformation of the sugar. The diabetogenic action produced by 5-thio-d-glucose is due, in part, to the ability of the analogue to interfere with cellular transport processes that use d-glucose.

Localization of the high-affinity glutamate transporter EAAC1 in rat kidney

1997 ◽  
Vol 273 (6) ◽  
pp. F1023-F1029 ◽  
Author(s):  
Chairat Shayakul ◽  
Yoshikatsu Kanai ◽  
Wen-Sen Lee ◽  
Dennis Brown ◽  
Jeffrey D. Rothstein ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Kidney ◽  
Cell Volume Regulation ◽  
Glutamate Transporter ◽  
Transport Systems ◽  
Kidney Cortex ◽  
Acid Base Balance ◽  
Western Blots ◽  
High Affinity

Most amino acids filtered by the glomerulus are reabsorbed in the kidney via specialized transport systems. Recently, the cDNA encoding a high-affinity glutamate transporter, EAAC1, has been isolated and shown to be expressed at high levels in the kidney. To determine the potential role of EAAC1 in renal acidic amino acid reabsorption, the distribution of EAAC1 mRNA and protein in rat kidney was examined. In situ hybridization revealed that EAAC1 mRNA is expressed predominantly in S2 and S3 segments of the proximal tubules and at low levels in the inner stripe of outer medulla and inner medulla. Polyclonal antibodies raised against the carboxy terminus of EAAC1 recognized a single band of ∼70 kDa on Western blots of membrane protein from kidney cortex and medulla. Immunofluorescence microscopy revealed intense signals in the luminal membrane of S2 and S3 segments and weaker signals in S1 segments, descending thin limbs of long-loop nephrons, medullary thick ascending limbs, and distal convoluted tubules. These results are consistent with EAAC1 encoding the previously described apical high-affinity glutamate transporter in the kidney that mediates reabsorption of acidic amino acids in tubules beyond early proximal tubule S1 segments. Potential additional roles of EAAC1 in acid/base balance, cell volume regulation, and amino acid metabolism are discussed.

AMINO ACID EXCRETION PATTERNS IN DEVELOPING RATS

1967 ◽  
Vol 45 (5) ◽  
pp. 867-872 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Acid Excretion ◽  
Human Infants ◽  
Rat Kidney Cortex ◽  
Progressive Development ◽  
Cortex Slices ◽  
Amino Acid Concentrations

Amino acid excretion patterns were studied in rats 2 to 12 weeks old. In general there was a decline in amino acid excretion over this period which paralleled that reported in human infants by other workers. The decrease was most marked for certain amino acids (glycine, histidine, and arginine). These changes in excretion are not explicable in terms of changes in plasma amino acid concentrations, nor is it likely that they result from differences in filtered load. They may reflect a progressive development of transport mechanisms for some amino acids over the period studied, in which case similar changes in the concentrating ability of rat kidney cortex slices would be predicted. Other possible explanations which are less readily tested include changes in permeability of the tubular cell membranes and differences in the glomerular filtering capacity relative to the amount of tubular tissue which has developed.

A comparison of the amino acid concentrating ability of the kidney cortex of newborn and mature rats

1968 ◽  
Vol 46 (2) ◽  
pp. 165-169 ◽  
Author(s):  
W. A. Webber ◽  
J. A. Cairns
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cell Layer ◽  
Rat Kidney ◽  
The Other ◽  
Kidney Cortex ◽  
Acid Transport ◽  
Newborn Rat ◽  
Rat Kidney Cortex ◽  
A Cell

It has frequently been demonstrated that there are multiple mechanisms for amino acid transport and that these function to maintain a favorable intracellular level of amino acids within cells. In some instances they also make possible the transport of amino acids from one face of a cell layer to the other. In general, developing tissues have a higher concentrating ability than mature tissues. In the kidney, however, it has been observed that the ability to reabsorb amino acids may be less effective in developing than in mature organisms. Studies were carried out to determine whether the newborn rat kidney cortex differed from mature cortex in its ability to concentrate a representative group of amino acids. In general, the patterns observed for the concentrative uptake of glycine, L-leucine, α-aminoisobutyric acid, L-aspartic acid, and L-lysine were the same. In all cases uptake was initially more rapid in the mature tissue, but the concentration ratios ultimately reached were higher in the newborn tissues. It is concluded that, as in other developing tissues, newborn rat kidney cortex has a high concentrating ability and might therefore be expected to reabsorb amino acids at least as effectively as mature cortex. However the observation that uptake is relatively slow initially suggests that although the ability to establish a gradient at equilibrium is high the capacity of the system is relatively low and this may account for the apparent low capacity of the immature kidney to reabsorb amino acids.

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