Inhibition of Sodium and Potassium Transport in Separated Renal Tubule Fragments Incubated in Extracts of Urine Obtained from Salt-Loaded Individuals

1972 ◽  
Vol 42 (5) ◽  
pp. 607-617 ◽  
Author(s):  
E. M. Clarkson ◽  
H. E. De Wardener
Keyword(s):  
Sodium Transport ◽  
Renal Tubule ◽  
Gel Filtration ◽  
Oral Intake ◽  
Potassium Transport ◽  
Intracellular Sodium ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Freeze Dried ◽  
Sodium And Potassium

1. Extracts of urine were prepared from salt-depleted and salt-loaded subjects by gel filtration of freeze-dried urine on Sephadex G-50. The extracts were dissolved and adjusted to physiological pH and electrolyte concentration. 2. Separated renal tubule fragments were prepared from rabbit kidney cortex and their intracellular sodium and potassium measured after incubation in the dissolved adjusted extracts. Those concerned with the measurement of intracellular sodium and potassium did not know the identity of the samples. 3. Extracts of urine from salt-loaded subjects inhibited the sodium and potassium transport of the tubules whereas extracts of urine from salt-depleted subjects had no effect. 4. Of ten known hormones that were tested, none had any inhibitory effect on the sodium transport of the tubule fragments. 5. It is concluded that the oral intake of large amounts of salt in normal subjects causes the appearance of an unknown substance in the urine which inhibits sodium transport in separated renal tubule fragments.

The Effect of Plasma from Blood Volume Expanded Dogs on Sodium and Potassium Transport of Renal Tubule Fragments

1970 ◽  
Vol 38 (5) ◽  
pp. 34P-34P
Author(s):  
E. M. Clarkson ◽  
L. B. Talner ◽  
H. E. de Wardener
Keyword(s):  
Blood Volume ◽  
Renal Tubule ◽  
Potassium Transport ◽  
Sodium And Potassium

scholarly journals Assay, purification and properties of mammalian d-2-hydroxy acid dehydrogenase

1969 ◽  
Vol 115 (1) ◽  
pp. 55-64 ◽  
Author(s):  
R. Cammack
Keyword(s):  
Hydroxy Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Sedimentation Coefficient ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Acid Oxidase ◽  
Animal Tissues ◽  
Acid Dehydrogenase ◽  
Purification And Properties

1. A new method is described for the measurement of d-2-hydroxy acid dehydrogenase in samples of animal tissues. 2. The distribution of the enzyme in a number of animals was determined. Of the animal tissues tested, the most active source of the enzyme was found to be rabbit kidney cortex. 3. The enzyme was purified from rabbit kidney to a stage at which it appears to be homogeneous in the analytical ultracentrifuge and on polyacrylamide-gel electrophoresis. 4. The molecular weight was estimated by gel filtration to be approx. 102000; combination of gelfiltration data and the sedimentation coefficient gave a value of 95000. 5. The purified enzyme has a spectrum typical of a flavoprotein. The change induced in the spectrum on addition of d-malate or d-lactate suggests the formation of a flavin semiquinone. 6. Flavin can be removed by treatment with acid ammonium sulphate, and activity can be restored to the inactive apoenzyme by addition of FAD, but not of FMN or riboflavin. 7. Studies of acceptor specificity showed that the enzyme has a relatively weak d-2-hydroxy acid oxidase activity.

Reduction of Potassium in Kidney Proximal Tubules to Aid in Electron Probe X-Ray Microanalysis of Calcium

1985 ◽  
Vol 43 ◽  
pp. 474-475
Author(s):  
A. LeFurgey ◽  
P. Ingram ◽  
L.J. Mandel
Keyword(s):  
Smooth Muscle ◽  
Proximal Tubule ◽  
Electron Probe ◽  
Clinical Applications ◽  
Proximal Tubules ◽  
Rabbit Kidney ◽  
Target Cells ◽  
X Ray ◽  
Freeze Dried

For quantitative determination of subcellular Ca distribution by electron probe x-ray microanalysis, decreasing (and/or eliminating) the K content of the cell maximizes the ability to accurately separate the overlapping K Kß and Ca Kα peaks in the x-ray spectra. For example, rubidium has been effectively substituted for potassium in smooth muscle cells, thus giving an improvement in calcium measurements. Ouabain, a cardiac glycoside widely used in experimental and clinical applications, inhibits Na-K ATPase at the cell membrane and thus alters the cytoplasmic ion (Na,K) content of target cells. In epithelial cells primarily involved in active transport, such as the proximal tubule of the rabbit kidney, ouabain rapidly (t1/2= 2 mins) causes a decrease2 in intracellular K, but does not change intracellular total or free Ca for up to 30 mins. In the present study we have taken advantage of this effect of ouabain to determine the mitochondrial and cytoplasmic Ca content in freeze-dried cryosections of kidney proximal tubule by electron probe x-ray microanalysis.

Thermal Property Measurements on Biological Materials at Subzero Temperatures

1991 ◽  
Vol 113 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Xuemei Bai ◽  
David E. Pegg
Keyword(s):  
Thermal Conductivity ◽  
Low Temperatures ◽  
The Self ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Low Viscosity ◽  
Subzero Temperatures ◽  
Liquid Samples ◽  
Thermal Probes ◽  
Low Ionic Strength

The self-heated thermistor technique was used to measure the thermal conductivity and thermal diffusivity of biomaterials at low temperatures. Thermal standards were selected to calibrate the system at temperatures from −10°C to −70°C. The thermal probes were constructed with a convection barrier which eliminates convection inside liquid samples of low viscosity, without affecting the conductivity and diffusivity results. Using this technique, the thermal conductivity and diffusivity of two organ perfusates (HP5 and HP5 + 2M glycerol), one kidney phantom (a low ionic strength gel), as well as rabbit kidney cortex have been measured from −10°C to −70°C.

Early contributions to the neurochemistry of sodium and potassium transport

1989 ◽  
Vol 14 (3) ◽  
pp. 243-248
Author(s):  
William L. Stahl ◽  
Phillip D. Swanson
Keyword(s):  
Potassium Transport ◽  
Sodium And Potassium
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