Selectivity of Probenecid Congeners for Different Organic Acid Transport Systems in Rabbit Renal Cortex

Seventeen probenecid congeners were tested as inhibitors of the simultaneous uptake of labelled o-iodohippurate and iodipamide into slices of rabbit renal cortex. Compounds with small substituents on the nitrogen were more inhibitory for o-iodohippurate, while compounds with larger lipophilic substituents were more inhibitory for iodipamide uptake. The results are interpreted in terms of differential inhibition of two transport systems: the classical hippurate or H-system and the liver-like L-system.