Transport mechanism of ceftibuten, a dianionic cephem, in rat renal brush-border membrane.
The uptake mechanism of ceftibuten by rat renal brush-border membrane vesicles was investigated. Uptake was found to be independent of a Na+ gradient and partially dependent on an inwardly directed H(+)-gradient. Competition experiments between ceftibuten and several compounds demonstrated that the peptide-like structural features of inhibitors are more essential than their charge properties for inhibiting uptake. Anionic compound, such as p-aminohippuric acid, also inhibited ceftibuten uptake by renal brush-border membrane vesicles in the presence of an H(+)-gradient. We conclude that ceftibuten, in spite of its anionic structure, is transported via the dipeptide transport systems, rather than the organic anion transport system.
Naasani
I
I
Department of Pharmacy, Hokkaido University Hospital, School of Medicine, Hokkaido University, Sapporo, Japan.
Sugawara
M
M
Kobayashi
M
M
Iseki
K
K
Miyazaki
K
K
D000818:Animals; D001692:Biological Transport; D000077722:Ceftibuten; D002511:Cephalosporins / Q000493:pharmacokinetics*; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008871:Microvilli / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013379:Substrate Specificity
D002511:Cephalosporins; D000077722:Ceftibuten