Pyrazinoate transport in the isolated perfused rabbit proximal tubule

The bidirectional tubular transport of pyrazinoate (PZA) was studied in the isolated perfused proximal S2 segment of rabbit kidney. PZA reabsorption was a mechanism of large capacity, temperature-dependent and requiring a normal Na+/K+-ATPase activity. PZA reabsorption was reversibly decreased when...

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Bibliographic Details
Published in:Pflügers Archiv 1986-12, Vol.407 (6), p.643-648
Main Authors: BESSEGHIR, K, ROCH-RAMEL, F
Format: Article
Language:English
Subjects:
4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid - pharmacology
Absorption
Animals
Biological and medical sciences
Biological Transport
Epithelium - metabolism
Ethoxzolamide - pharmacology
Female
Fundamental and applied biological sciences. Psychology
In Vitro Techniques
Kidney Tubules, Proximal - drug effects
Kidney Tubules, Proximal - metabolism
Lactates - metabolism
Lactic Acid
Male
Ouabain - pharmacology
p-Aminohippuric Acid - pharmacology
Pyrazinamide - analogs & derivatives
Pyrazinamide - metabolism
Rabbits
Vertebrates: urinary system
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Summary:The bidirectional tubular transport of pyrazinoate (PZA) was studied in the isolated perfused proximal S2 segment of rabbit kidney. PZA reabsorption was a mechanism of large capacity, temperature-dependent and requiring a normal Na+/K+-ATPase activity. PZA reabsorption was reversibly decreased when lactate was added to the perfusate, indicating that it might occur through the sodium-lactate cotransport. The addition of PAH to the bath had a slight stimulatory effect on PZA reabsorption, suggesting a component of anion exchange in the overall PZA reabsorption. However, SITS added to either the perfusate or the bathing medium induced a non-significant decrease in PZA reabsorption, confirming the minor part of an anion exchange mechanism in this reabsorptive process. PZA reabsorption was not affected by the establishment of a bath-to-lumen H+ gradient, and was only moderately decreased after carbonic anhydrase inhibition by ethoxyzolamide, in opposition to what is known for the reabsorbed anion salicylate. The secretory transport of PZA was saturable and also dependent on a normal Na+/K+-ATPase activity. It is concluded that PZA is bidirectionally transported by facilitated mechanisms in the rabbit proximal S2 segment, one major reabsorptive mechanism appearing to be a sodium-anion cotransport, which might be the sodium-lactate reabsorbing mechanism.
ISSN:0031-6768
1432-2013
DOI:10.1007/BF00582646