scholarly journals Regulation of Organic Cation Transport in Isolated Mouse Proximal Tubules Involves Complex Changes in Protein Trafficking and Substrate Affinity

2012 ◽  
Vol 30 (1) ◽  
pp. 269-281 ◽  
Author(s):  
Denise Guckel ◽  
Giuliano Ciarimboli ◽  
Hermann Pavenstädt ◽  
Eberhard Schlatter
Keyword(s):  
Protein Trafficking ◽  
Organic Cation ◽  
Cation Transport ◽  
Proximal Tubules ◽  
Organic Cation Transport ◽  
Substrate Affinity

Peritubular organic cation transport in isolated rabbit proximal tubules

1994 ◽  
Vol 266 (3) ◽  
pp. F450-F458 ◽  
Author(s):  
C. E. Groves ◽  
K. K. Evans ◽  
W. H. Dantzler ◽  
S. H. Wright
Keyword(s):  
Organic Cation ◽  
High Capacity ◽  
Organic Cation Transporter ◽  
Cation Transport ◽  
Proximal Tubules ◽  
Organic Cation Transport ◽  
Inhibitory Potency ◽  
Renal Proximal Tubules ◽  
Michaelis Constants ◽  
Maximal Capacity

The physiological characteristics of peritubular organic cation transport were examined by measuring the transport of the organic cation tetraethylammonium (TEA) in rabbit renal proximal tubule suspensions and isolated nonperfused rabbit renal proximal tubules. Peritubular organic cation transport in both single S2 segments and suspensions of isolated renal proximal tubules was found to be a high-capacity, high-affinity, carrier-mediated process. For tubule suspensions, the maximal capacity of the carrier for TEA (Jmax) and the concentration of TEA at 1/2 Jmax (Kt) (1.49 +/- 0.21 nmol.min-1.mg dry wt-1 and 131 +/- 16 microM, respectively), did not differ significantly from those measured in single S2 segments (Jmax, 1.16 +/- 0.075 nmol.min-1.mg dry wt-1; Kt, 108 +/- 10 microM). In addition, the pattern of inhibition of peritubular TEA transport by long-chain n-tetraalkylammonium compounds (n = 1-5) was both qualitatively and quantitatively similar in single S2 segments and tubule suspensions, exhibiting an increase in inhibitory potency with increasing alkyl chain length. For example, in tubule suspensions, apparent Michaelis constants for inhibition of TEA uptake ranged from 1.3 mM for tetramethylammonium (TMA) to 0.8 microM for tetrapentylammonium (TPeA). To determine whether these compounds were substrates for the peritubular organic cation transporter, their effect on the efflux of [14C]TEA from tubule suspensions was examined. A concentration of 0.5 mM of the short-chain tetraalkyls TMA or TEA increased the efflux of [14C]TEA (i.e., trans-stimulated) from tubules in suspension. The longer-chain tetraalkyls tetrapropylammonium, tetrabutylammonium, and TPeA all decreased the efflux of [14C]TEA from tubules in suspension; TPeA completely blocked efflux.(ABSTRACT TRUNCATED AT 250 WORDS)

DIGITAL FLUORESCENCE IMAGING OF ORGANIC CATION TRANSPORT IN FRESHLY ISOLATED RAT PROXIMAL TUBULES

2005 ◽  
Vol 34 (3) ◽  
pp. 339-342 ◽  
Author(s):  
Frank Pietruck ◽  
Markus Horbelt ◽  
Thorsten Feldkamp ◽  
Katrin Engeln ◽  
Stefan Herget-Rosenthal ◽  
...  
Keyword(s):  
Fluorescence Imaging ◽  
Organic Cation ◽  
Cation Transport ◽  
Proximal Tubules ◽  
Organic Cation Transport ◽  
Digital Fluorescence Imaging ◽  
Isolated Rat

scholarly journals Properties and Regulation of Organic Cation Transport in Freshly Isolated Human Proximal Tubules

2001 ◽  
Vol 276 (36) ◽  
pp. 33741-33746 ◽  
Author(s):  
Gesine Pietig ◽  
Thomas Mehrens ◽  
Jochen R. Hirsch ◽  
Ibrahim Çetinkaya ◽  
Hansjürgen Piechota ◽  
...  
Keyword(s):  
Organic Cation ◽  
Cation Transport ◽  
Proximal Tubules ◽  
Organic Cation Transport

Specificity of basolateral organic cation transport in snake renal proximal tubules

1996 ◽  
Vol 270 (5) ◽  
pp. R1025-R1030
Author(s):  
Y. K. Kim ◽  
W. H. Dantzler
Keyword(s):  
Organic Cation ◽  
Basolateral Membrane ◽  
Cation Transport ◽  
Inhibitory Effect ◽  
Proximal Tubules ◽  
Organic Cation Transport ◽  
Renal Proximal Tubules ◽  
Basolateral Side ◽  
Michaelis Constants ◽  
Kinetics Of

We examined the specificity of basolateral organic cation transport in isolated snake (Thamnophis spp.) renal proximal tubules by determining the inhibitory effect of a series of n-tetraalkylammonium (n-TAA) compounds (n = 1-5) on the basolateral uptake of [3H]tetraethylammonium (TEA). The inhibitory potency increased with increasing alkyl chain length, with the apparent Michaelis constants for inhibition of TEA uptake ranging from 3.3 mM for tetramethylammonium (TMA) to 1.0 microM for tetrapentylammonium (TPeA). Thus the apparent affinity of the carrier for n-TAA compounds increases with their increasing hydrophobicity. Because previous data suggested that TEA transport across the basolateral membrane may be asymmetrical and that the exit step may be regulated differently from the entry step, we examined the kinetics of [3H]TEA efflux across the basolateral membrane, Efflux, like entry, occurred by a saturable process that could be described adequately by Michaelis-Menten kinetics. However, the concentration of TEA at one-half Jmax (Kt) for efflux (approximately 110 microM) was about six times the Kt for uptake (approximately 18 muM), indicating that the affinity of the carrier for TEA is greater in the uptake direction than in the efflux direction or that there are separate carriers with different affinities for uptake and efflux. In either case, this difference would favor movement of TEA taken up at the basolateral side across the cells and into the lumen over movement back into the peritubular fluid.

Properties and regulation of organic cation transport in freshly isolated mouse proximal tubules analyzed with a fluorescence reader-based method

2011 ◽  
Vol 462 (2) ◽  
pp. 359-369 ◽  
Author(s):  
Svenja K. Holle ◽  
Giuliano Ciarimboli ◽  
Bayram Edemir ◽  
Ute Neugebauer ◽  
Hermann Pavenstädt ◽  
...  
Keyword(s):  
Organic Cation ◽  
Cation Transport ◽  
Proximal Tubules ◽  
Organic Cation Transport

Functional Impairment of Renal Organic Cation Transport in Experimental Diabetes

2002 ◽  
Vol 90 (4) ◽  
pp. 181-186 ◽  
Author(s):  
Brett Grover ◽  
Christopher Auberger ◽  
Rangaprasad Sarangarajan ◽  
William Cacini
Keyword(s):  
Functional Impairment ◽  
Organic Cation ◽  
Experimental Diabetes ◽  
Cation Transport ◽  
Organic Cation Transport

Regulation of organic cation transport

2004 ◽  
Vol 449 (5) ◽  
pp. 423-441 ◽  
Author(s):  
Giuliano Ciarimboli ◽  
Eberhard Schlatter
Keyword(s):  
Organic Cation ◽  
Cation Transport ◽  
Organic Cation Transport

POSTNATAL DEVELOPMENT OF ORGANIC CATION TRANSPORT IN THE RAT LIVER

1998 ◽  
Vol 37 (2) ◽  
pp. 131-136 ◽  
Author(s):  
F. MARTEL ◽  
M.J. MARTINS ◽  
C. CALHAU ◽  
C. HIPÓLITO-REIS ◽  
I. AZEVEDO
Keyword(s):  
Postnatal Development ◽  
Rat Liver ◽  
Organic Cation ◽  
Cation Transport ◽  
Organic Cation Transport
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