Perfusion-Dependent Selective Induction of Prostaglandin Biosynthesis Activity in Rabbit Kidney Cortex

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.

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Carbonic anhydrase XII mRNA encodes a hydratase that is differentially expressed along the rabbit nephron

AJP Renal Physiology ◽

10.1152/ajprenal.00370.2001 ◽

2003 ◽

Vol 284 (2) ◽

pp. F399-F410 ◽

Cited By ~ 8

Author(s):

George J. Schwartz ◽

Anne M. Kittelberger ◽

Richard H. Watkins ◽

Michael A. O'Reilly

Keyword(s):

Carbonic Anhydrase ◽

Transmembrane Protein ◽

Proximal Tubules ◽

Rabbit Kidney ◽

Kidney Cortex ◽

Thick Ascending Limb ◽

Basolateral Membranes ◽

Collecting Ducts ◽

Straight Tubules ◽

Hydratase Activity

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.

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Stimulation of p-aminohippuric acid transport in rabbit kidney cortex by parathyroid hormone and adenosine 3′,5′-cyclic monophosphate

Biochemical Pharmacology ◽

10.1016/0006-2952(76)90299-9 ◽

1976 ◽

Vol 25 (2) ◽

pp. 219-220 ◽

Cited By ~ 3

Author(s):

Ian Kippen ◽

Kiyoshi Kurokawa ◽

James R. Klinenherg

Keyword(s):

Parathyroid Hormone ◽

Rabbit Kidney ◽

Kidney Cortex ◽

Acid Transport ◽

Cyclic Monophosphate ◽

Stimulation Of

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Proximal tubule volume regulation in hypo-osmotic media: intracellular K+, Na+, and Cl-.

Journal of the American Society of Nephrology ◽

10.1681/asn.v12211 ◽

1990 ◽

Vol 1 (2) ◽

pp. 211-218

Author(s):

L Rome ◽

C Lechene ◽

J J Grantham

Keyword(s):

Cell Volume ◽

Volume Regulation ◽

Cell Volume Regulation ◽

Rabbit Kidney ◽

Kidney Cortex ◽

Volume Regulatory Decrease ◽

Osmotic Change ◽

Electrolyte Loss ◽

The Difference

This study sought to measure the net loss of intracellular K+, Na+, and Cl- that accompanied isosmotic cell volume regulation in hypotonic media and to determine if electrolyte loss depended on the rate at which the extracellular osmolality was reduced. Isolated nonperfused proximal S2 segments from rabbit kidney cortex were studied in vitro. Gradual lowering of osmolality from 295 to 150 mOsm/kg at a rate of 2 mOsm/kg/min did not cause an increase in tubule cell volume until the medium osmolality decreased below 190 mOsm/kg. By contrast, tubules rapidly bathed in low osmolality media exhibited classical osmometric swelling followed by incomplete volume regulatory decrease. Volume regulation associated with gradual and rapid lowering of osmolality was accompanied by the net loss of intracellular K+, Na+, and Cl- (measured by electron probe); however, the temporal pattern of electrolyte loss depended on the rate of osmotic change. With gradual lowering of osmolality, cell K+ content did not decrease significantly until osmolality was lowered below 200 mOsm/kg, whereas Cl- was lost at the 200 mOsm/kg level and below. With rapid lowering of osmolality, cell K+ content was strikingly decreased at the 200 mOsm/kg level, but Cl- did not change appreciably until osmolality was decreased to 150 mOsm/kg. Cell Na+ content decreased in hypo-osmotic media, but the magnitude was relatively small. During volume regulation that accompanied either gradual or rapid lowering of medium osmolality from 295 to 150 mOsm/kg, intracellular osmolal gap, the difference between medium osmolality and the sum of intracellular concentrations of K+, Na+, and Cl- decreased 87 and 58 mOsm/kg, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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Expression of Na+-independent amino acid transport in Xenopus laevis oocytes by injection of rabbit kidney cortex mRNA

Biochemical Journal ◽

10.1042/bj2810717 ◽

1992 ◽

Vol 281 (3) ◽

pp. 717-723 ◽

Cited By ~ 34

Author(s):

J Bertran ◽

A Werner ◽

G Stange ◽

D Markovich ◽

J Biber ◽

...

Keyword(s):

Amino Acids ◽

Xenopus Laevis ◽

Transport System ◽

Sucrose Density Gradient ◽

Rabbit Kidney ◽

Kidney Cortex ◽

Xenopus Laevis Oocytes ◽

Transport Pathways ◽

Arginine Uptake ◽

Dose Dependent Increase

Poly(A)+ mRNA was isolated from rabbit kidney cortex and injected into Xenopus laevis oocytes. Injection of mRNA resulted in a time- and dose-dependent increase in Na(+)-independent uptake of L-[3H]alanine and L-[3H]arginine. L-Alanine uptake was stimulated about 3-fold and L-arginine uptake was stimulated about 8-fold after injection of mRNA (25-50 ng, after 3-6 days) as compared with water-injected oocytes. T.I.C. of oocyte extracts suggested that the increased uptake actually represented an increase in the oocyte content of labelled L-alanine and L-arginine. The expressed L-alanine uptake, obtained by subtracting the uptake in water-injected oocytes from that in mRNA-injected oocytes, showed saturability and was inhibited completely by 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid (BCH) and L-arginine. The expressed L-arginine uptake in mRNA-injected oocytes also showed saturability, being completely inhibited by L-dibasic amino acids) and partially inhibited by BCH. Expression of both L-alanine and L-arginine uptake showed clear cis-inhibition by cationic (e.g. L-arginine) and neutral (e.g. L-leucine) amino acids. In all, this points to the expression of a Na(+)-independent transport system with broad specificity (i.e. b degree, (+)-like). In addition, part of the expressed uptake of L-arginine could be due to a system y(+)-like transporter. After size fractionation through a sucrose density gradient, the mRNA species encoding these increased transport activities (Na(+)-independent transport of L-alanine and of L-arginine) were found in fractions of an average mRNA chain-length of 1.8-2.4 kb. On the basis of these results, we conclude that Na(+)-independent transport system(s) for L-alanine and L-arginine from rabbit renal cortical tissues, most likely proximal tubules, are expressed in Xenopus laevis oocytes. These observations may represent the first steps towards expression and cloning of these transport pathways.

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