Age-dependent renal accumulation of cephaloridine in the rabbit.

The accumulation of cephaloridine in the renal cortex of the rabbit was studied in vitro and in vivo in rabbits of various ages. The cortical concentration of cephaloridine, the cortex/serum ratio, and the slice/medium ratio determined by incubation of cortical slices in cephaloridine-containing media rose from birth to adult levels at approximately 1 month of age. Pretreatment with procaine penicillin G stimulated the ability to accumulate cephaloridine in vitro and in vivo. The data indicate that the lack of susceptibility of immature rabbits to cephaloridine nephrotoxicity is due to the lack of development of the anionic transport system which is apparently necessary to achieve the high cortical concentrations of cephaloridine that result in renal injury.