p-Aminohippurate transport in rat renal brush-border membranes: a potential-sensitive transport system and an anion exchanger.
Transport mechanisms of p-aminohippurate (PAH) were investigated in rat renal brush-border membrane vesicles. The uptake of PAH was stimulated by an inside-positive membrane potential created by K+ and valinomycin. This potential-stimulated uptake of PAH was inhibited by various anion transport inhibitors and was saturable. In addition, PAH uptake in the presence of valinomycin was linearly increased in proportion to log[K+]out/[K+]in. On one hand, PAH uptake was stimulated by [14C]PAH/PAH or [14C]PAH/Cl- exchange, and the [14C]PAH/PAH exchange was insensitive to the membrane potential. The uptake by the exchanger was also inhibited by anion transport inhibitors, but the potential-stimulated uptake of PAH was more sensitive to furosemide and 4,4'-diisothiocyano-2,2'-disulfonic stilbene. On the contrary, [14C]PAH/PAH exchange was more sensitive to urate than the potential-stimulated uptake of PAH. These findings indicate that PAH is transported by two distinct transport systems in rat renal brush-border membranes, a potential-sensitive transport system and an anion exchanger.
Ohoka
K
K
Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Japan.
Takano
M
M
Okano
T
T
Maeda
S
S
Inui
K
K
Hori
R
R
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002712:Chlorides / Q000493:pharmacokinetics; D004058:Diffusion; D005665:Furosemide / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D007474:Ion Exchange; D007668:Kidney / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D008871:Microvilli / Q000378:metabolism; D011188:Potassium / Q000493:pharmacokinetics; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014527:Uric Acid / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology; D010130:p-Aminohippuric Acid / Q000493:pharmacokinetics*
D002712:Chlorides; D011506:Proteins; D014634:Valinomycin; D014527:Uric Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D005665:Furosemide; D005947:Glucose; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D011188:Potassium; D010130:p-Aminohippuric Acid