title: Accumulation of [14C]urate and [3H]PAH in isolated proximal tubular segments of the rabbit kidney.
abstract: Segments of rabbit proximal tubules (S1, S2, and S3) were incubated (30 min, 37 degrees C, pH 7.4) in Ringer solution (under O2) containing [14C]urate or [3H]PAH and probenecid, pyrazinoic acid (PZA), urate, or PAH, all at 1 mM. The ratio [14C]urate (counts/min per nanoliter of tubular cell water)/(counts/min per nanoliter of incubation medium) (T/M) reached 2.92 +/- 0.31 (mean +/- SE; n = 15), 6.08 +/- 0.42 (n = 42), and 1.72 +/- 0.31 (n = 14) for S1, S2, and S3 segments, respectively. In these segments the uptake of [3H]PAH was 22.7 +/- 4.6 (n = 19), 133 +/- 18.9 (n = 24), and 66.2 +/- 15.3 (n =0). The accumulation of [14C]urate was saturated at 2 x 10(-4) M in the medium, and that of [3H]PAH at 7 x 10(-5) M in the medium. Secretory transport was saturated at the same bath PAH concentration in perfused tubules. Urate and PAH transports inhibited each other, thus suggesting a common transport mechanism mainly located in the S2 segment. Probenecid was a strong and PZA a weak inhibitor of this transport system.
mesh_terms: D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002250:Carbon Radioisotopes; D005260:Female; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008297:Male; D010477:Perfusion; D011339:Probenecid / Q000494:pharmacology; D011718:Pyrazinamide / Q000494:pharmacology; D011817:Rabbits; D014316:Tritium; D014527:Uric Acid / Q000378:metabolism* / Q000494:pharmacology; D010130:p-Aminohippuric Acid / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000618:Aminohippuric Acids; D002250:Carbon Radioisotopes; D014316:Tritium; D014527:Uric Acid; D011718:Pyrazinamide; D011339:Probenecid; D010130:p-Aminohippuric Acid