title: Transport mechanism of ceftibuten, a dianionic cephem, in rat renal brush-border membrane.
abstract: 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.
authors.affiliation: Department of Pharmacy, Hokkaido University Hospital, School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Naasani
authors.forename: M
authors.initials: M
authors.lastname: Sugawara
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: K
authors.initials: K
authors.lastname: Iseki
authors.forename: K
authors.initials: K
authors.lastname: Miyazaki
mesh_terms: 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
chemical_list: D002511:Cephalosporins; D000077722:Ceftibuten