scholarly journals Kininogenase activity in plasma membranes and cell organelles from rabbit kidney cortex: Subcellular localization of renal kallikrein by free-flow electrophoresis and density-gradient fractionation

1980 ◽  
Vol 18 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Hans G. Heidrich ◽  
Reinhard Geiger
1972 ◽  
Vol 128 (5) ◽  
pp. 1319-1328 ◽  
Author(s):  
S. J. Quirk ◽  
G. B. Robinson

1. Brush borders were isolated from rabbit kidney-cortex homogenates by rate-zonal centrifugation through a sucrose density gradient in a B-XIV zonal rotor, followed by differential centrifugation. 2. The method of preparation gave brush borders of high purity with a reasonable yield. The morphological appearance supported the evidence from enzymic and chemical investigations, that the brush borders were only slightly contaminated with endoplasmic reticulum, mitochondria, lysosomes and nuclei. 3. The molar ratio of cholesterol to phospholipid lay within the range found in other plasma membranes, but the carbohydrate content was double that found in liver plasma membranes. 4. Alkaline phosphatase, maltase, trehalase and aminopeptidase were major enzymic constituents of the brush borders, and had an approximately equal yield and enrichment, but none of these enzymes fulfilled the criteria for marker enzymes. 5. Mg2+-dependent and Na+,K+-dependent adenosine triphosphatases, although found in brush borders, had low yields and low enrichments.


1982 ◽  
Vol 92 (2) ◽  
pp. 505-513 ◽  
Author(s):  
A Vandewalle ◽  
B Köpfer-Hobelsberger ◽  
H G Heidrich

Free-flow electrophoresis allows the separation of different cell populations from a cell suspension isolated from rabbit kidney cortex after perfusion of the kidneys with a calcium-binder, followed by gentle mechanical treatment. After electrophoretic separation, analysis of the adenylate cyclase activities after stimulation by various hormones allows the precise determination of the origin of the cell populations with different electrophoretic mobilities. Adenylate cyclase from the slow-moving main cell population was only sensitive to parathyroid hormone. These cells had also high alkaline phosphatase content, further demonstrating their proximal origin. The various fast-moving cell populations had adenylate cyclase sensitive to isoproterenol and arginine vasopressin but were less sensitive to parathyroid hormone than the slow-moving cells. Their alkaline phosphatase content was also much lower. This indicates that these fast-moving cell populations originate from both the granulous segment of the distal tubule and from the collecting ducts. The adenylate cyclase activity and the cyclic AMP contents of isolated proximal cells maintained in culture medium were also investigated.


1979 ◽  
Vol 178 (3) ◽  
pp. 549-557 ◽  
Author(s):  
P Gmaj ◽  
H Murer ◽  
R Kinne

Basal-lateral-plasma-membrane vesicles and brush-border-membrane vesicles were isolated from rat kidney cortex by differential centrifugation followed by free-flow-electrophoresis. Ca2+ uptake into these vesicles was investigated by a rapid filtration method. Both membranes show a considerable binding of Ca2+ to the vesicle interior, making the analysis of passive fluxes in uptake experiments difficult. Only the basal-lateral-plasma-membrane vesicles exhibit an ATP-dependent pump activity which can be distinguished from the activity in mitochondrial and endoplasmic reticulum by virtue of the different distribution during free-flow electrophoresis and its lack of sensitivity to oligomycin. The basal-lateral plasma membranes contain in addition a Na+/Ca2+-exchange system which mediates a probably rheogenic counter-transport of Ca2+ and Na+ across the basal cell border. The latter system is probably involved in the secondary active Na+-dependent and ouabain-inhibitable Ca2+ reabsorption in the proximal tubule, the ATP-driven system is probably more important for the maintenance of a low concentration of intracellular Ca2+.


1995 ◽  
Vol 95 (3) ◽  
pp. 399-408 ◽  
Author(s):  
Elena Toll ◽  
Federico J. Castillo ◽  
Pierre Crespi ◽  
Michele Crevecoeur ◽  
Hubert Greppin

1991 ◽  
Vol 113 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Xuemei Bai ◽  
David E. Pegg

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.


2003 ◽  
Vol 284 (2) ◽  
pp. F399-F410 ◽  
Author(s):  
George J. Schwartz ◽  
Anne M. Kittelberger ◽  
Richard H. Watkins ◽  
Michael A. O'Reilly

Membrane-bound carbonic anhydrase (CA) facilitates acidification in the kidney. Although most hydratase activity is considered due to CA IV, some in the basolateral membranes could be attributed to CA XII. Indeed, CA IV is glycosylphosphatidylinositol anchored, connoting apical polarization, but CA IV immunoreactivity has been detected on basolateral membranes of proximal tubules. Herein, we determined whether CA XII mRNA was expressed in acidifying segments of the rabbit nephron. The open reading frame of CA XII was sequenced from a rabbit kidney cortex cDNA library; it was 83% identical to human CA XII and coded for a 355-amino acid single-pass transmembrane protein. Northern blot analysis revealed an abundant 4.5-kb message in kidney cortex, medulla, and colon. By in situ hybridization, CA XII mRNA was expressed by proximal convoluted and straight tubules, cortical and medullary collecting ducts, and papillary epithelium. By RT-PCR, CA XII mRNA was abundantly expressed in cortical and medullary collecting ducts and thick ascending limb of Henle's loop; it was also expressed in proximal convoluted and straight tubules but not in glomeruli or S3 segments. FLAG-CA XII of ∼40 kDa expressed in Escherichia coli showed hydratase activity that was inhibited by 0.1 mM acetazolamide. Unlike CA IV, expressed CA XII activity was inhibited by 1% SDS, suggesting insufficient disulfide linkages to stabilize the molecule. Western blotting of expressed CA XII with two anti-rabbit CA IV peptide antibodies showed no cross-reactivity. Our findings indicate that CA XII may contribute to the membrane CA activity of proximal tubules and collecting ducts.


1976 ◽  
Vol 193 (1112) ◽  
pp. 217-234 ◽  

A study has been made of ouabain binding and the formation of phosphoprotein from ATP and inorganic phosphate (P i ) with plasma membranes from rabbit and guinea-pig kidney cortex. The aim of the work was first to see whether apparently conflicting results in the literature arise from membranes being prepared by different methods and, secondly, to evaluate the results in relation to the Na pump mechanism. Three different methods were used to prepare membranes, types A, Au and B. The preparations differed markedly when ouabain binding was supported by Mg alone both in the amount bound and in the affinity. Mgdependent binding was influenced by 1 mM P i but the extent of stimulation varied according to the preparations. The main effect of P i was to decrease the equilibrium dissociation constant marginally for type A membranes but eightfold for type B membranes. In contrast, the maximum number of binding sites was little affected. The membrane affinity for ouabain in relation to Mg and P i therefore depended on the method of preparation. In the reaction with Mg-ATP, type Au and B membranes were both phosphorylated to about the same extent. On the other hand, they reacted differently with P i , type B membranes being phosphorylated (in the presence of Mg and ouabain) to the same extent as with ATP, whereas under the same conditions, type Au membranes gave only 15 % of the phosphorylation found with ATP. The phosphoprotein, however formed, whether from ATP or P i , or type Au or type B membranes, migrated in the same way on gel electrophoresis to give a relative molecular mass of approximately 90000. With each preparation, over a tenfold range of ATPase activity, there was a constant value of 1.2 in the ratio of the maximum phosphorylation by ATP compared with the maximum number of ouabain-binding sites. These results show that membranes prepared in different ways exhibit some consistent properties of the Na pump but also striking anomalies. In view of likely morphological differences in the preparations, it is concluded that the inconsistent features, notably the responses to Mg and P i , are an unreliable guide to the pump mechanism.


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