Kinetic analysis of the renal handling of 2,2-bis(p-chlorophenyl) acetic acid by the rat

JB Pritchard

The kinetics of uptake and efflux of organic acids in rat renal cortical slices were used to examine the affinity of 2,2-bis(p- chlorophenyl)acetic acid (DDA) for the organic acid transport system and to assess intracellular binding of this polar 1,1,1-trichloro-2,2- bis(p-chlorophenyl)ethane (DDT) metabolite. As judged by its ability to inhibit p-aminohippuric acid transport, DDA was a potent competitive inhibitor, almost as strong as probenecid, the classical inhibitor of this system. Efflux of DDA from slices demonstrated that the bulk (85%) of the DDA within the slice was reversibly bound to proteins or other macromolecules. Cortical slices incubated 60 minutes with 10 micron DDA contained a total concentration of 160 micron DDA within the tubular cells, but the actual free concentration in the cells was only 20 to 30 micron. Thus, although DDA was accumulated against a concentration gradient by the kidney, the gradient was much smaller than the measured tissue/medium ratio. Potential consequences of DDA exposure through its interaction with the organic acid system and roles of DDA binding sites in the toxicity and transport of DDA are discussed.

Volume 205, Issue 1, pp. 9-18, 04/01/1978
Copyright © 1978 by American Society for Pharmacology and Experimental Therapeutics