In vitro uptake of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) by renal cortical tissue of rabbits and rats

The active transport of 2,4-D and 2,4,5-T by renal cortical slices of rats and rabbits has been characterized with in vitro techniques. Renal cortical slices, prepared from both species, accumulate 2,4-D and 2,4,5-T, although greater uptake, was noted with rabbit tissue. Nitrogen and various metabolic inhibitors reduced the uptakes. This indicates that these processes are energy dependent. The enhancement of accumulation by the addition of certain metabolic substrates, e.g. acetate, lactate, provides evidence that both organic acid herbicides are transported by the renal organic anion mechanism. Potassium-ion stimulation also supports this concept. It is concluded that the renal tubular transport by the organic anion mechanism may account for the relatively rapid disappearance of these compounds, which in turn may contribute to their low toxicity.