Transport of the organic cation N1-methylnicotinamide by the rabbit proximal tubule. I. Accumulation in the isolated nonperfused tubule.

Details

Serval ID
serval:BIB_A1338057458E
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Transport of the organic cation N1-methylnicotinamide by the rabbit proximal tubule. I. Accumulation in the isolated nonperfused tubule.
Journal
Journal of Pharmacology and Experimental Therapeutics
Author(s)
Besseghir K., Mosig D., Roch-Ramel F.
ISSN
0022-3565
Publication state
Published
Issued date
05/1990
Peer-reviewed
Oui
Volume
253
Number
2
Pages
444-451
Language
english
Abstract
Isolated nonperfused rabbit renal proximal tubules were used to investigate the basolateral step of transport of the organic cation N1-methylnicotinamide (NMN). NMN accumulation was highest and saturable in S2 and S3 segments, but lowest and nonsaturable in S1 segments. In S1 segments, accumulation of [3H]-NMN (0.5-8 microM in the bath) resulted in an average tubular water/medium concentration ratio (T/M) of 8.2, whereas in S2 and S3 segments T/M averaged 19.5 and 18.6, respectively. At these concentrations, about 30% of the label was attached in all segments to a metabolite comigrating with nicotinamide. KCN (10(-2) M) or ouabain (10(-4) M) reduced T/M to about 8 for all segments. NMN accumulation was inhibited (to a T/M of about 3 with mepiperphenidol) by other organic cations (10(-5)-10(-3) M) with the potency sequence mepiperphenidol greater than tetraethylammonium = quinine greater than morphine, these organic cations having no effect on p-aminohippurate accumulation, except for the highest concentration of quinine (10(-3) M). After correction for metabolism, NMN accumulation could be accounted for by simple electrochemical equilibrium across the basolateral membrane. The basolateral step of NMN transport appears therefore to be a carrier-mediated diffusion, in opposition to the active basolateral accumulation described for tetraethylammonium.
Keywords
Animals, Chromatography, High Pressure Liquid, Drug Interactions, Female, Kidney Tubules, Proximal/metabolism, Male, Niacinamide/analogs & derivatives, Niacinamide/analysis, Potassium Cyanide/pharmacology, Rabbits, p-Aminohippuric Acid/analysis, p-Aminohippuric Acid/pharmacokinetics
Pubmed
Web of science
Create date
17/07/2009 16:23
Last modification date
20/08/2019 15:07
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