Transport of cephalosporin antibiotics in rat renal basolateral membranes.

Transport mechanisms of cephalosporin antibiotics in rat renal basolateral membranes have been studied in isolated membrane vesicles. Uptake of [14C]p-aminohippurate, a typical organic anion, by basolateral membrane vesicles was enhanced when membrane vesicles were preloaded with unlabelled p-aminohippurate (counter-transport). Cephalosporins such as cephradine, cephalexin, and cefazolin inhibited the counter-transport of [14C]p-aminohippurate, as did unlabelled p-aminohippurate and probenecid. In contrast, cephalexin did not affect the uptake of [3H]tetraethylammonium, an organic cation, by basolateral membrane vesicles. These results suggest that most cephalosporins are transported via organic anion transport systems in rat renal basolateral membranes.