title: Urate and p-aminohippurate transport in rat renal basolateral vesicles.
abstract: We examined the transport of urate in basolateral membrane vesicles from the rat kidney and determined the relationship between the transport of urate and p-aminohippurate (PAH). Urate was not converted to allantoin, and the uptake of urate represented transport into an osmotically active intravesicular space. The 10-s uptake of 53 microM [14C]urate in basolateral vesicles was inhibited 39 +/- 6, 49 +/- 10, and 35 +/- 3% by (in mM) external 2.4 probenecid, 2.4 DIDS, and 1.4 unlabeled urate, respectively. The 10-s uptake of 353 microM [14C]urate was trans-stimulated 82 +/- 8% by preloading basolateral vesicles with 1.5 mM unlabeled urate. The uptake of urate was stimulated by an outwardly directed gradient for Cl- (Cl-in = 25 mM, Cl-out = 5 mM). This effect was not consequent to a more electropositive intravesicular space, as monitored by the voltage-sensitive sodium-L-malate cotransport system. The Cl- gradient-stimulated component of urate uptake in basolateral vesicles was not cis-inhibited by 4.8 mM PAH, whereas Cl gradient-stimulated urate uptake in brush border vesicles was cis-inhibited 43 +/- 5% by PAH. In the absence of Cl-, 4.8 mM PAH did not cis-inhibit, and 5.4 mM PAH or 6.4 mM lactate did not trans-stimulate the uptake of urate in basolateral vesicles, contrasting with results obtained with brush border vesicles. The uptake of urate in basolateral vesicles was not stimulated by external Na+ relative to K+, Li+, or Cs+. In contrast, PAH uptake in basolateral vesicles was stimulated 87 +/- 9% by external Na+.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002712:Chlorides / Q000494:pharmacology; D007474:Ion Exchange; D007668:Kidney / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D008566:Membranes / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D014527:Uric Acid / Q000378:metabolism*; D010130:p-Aminohippuric Acid / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000618:Aminohippuric Acids; D002712:Chlorides; D007773:Lactates; D014527:Uric Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D012964:Sodium; D011339:Probenecid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D011188:Potassium; D010130:p-Aminohippuric Acid