Renal transport and renal metabolism of 2, 4, 5-trichlorophenoxyacetate by the chicken

In vitro and in vivo renal tubular transport of 2,4,5-trichlorophenoxyacetate (2,4,5-T), a hormone-type herbicide, was studied in the chicken. Renal cortical slices incubated with 14C-labeled 2,4,5-T demonstrated a slice-to-medium ratio of the 14C-label of 26 after 2 hr of incubation. This accumulation was inhibited significantly by probenecid, phenol red, dinitrophenol and iodoacetamide. In vitro metabolism of 2,4,5-T was apparent in the renal slice studies; at least two metabolites were found by electrophoretic analysis. Even though chicken liver slices were able to accumulate 2,4,5-T, the accumulated herbicide was not metabolized. In addition, chicken kidney slices metabolized 2,4,5-T to a much greater extent than did rat or rabbit kidney slices, which produced only negligible amounts of metabolites. When [14C]-2,4,5-T was infused into the renal portal system of the chicken, the 14C-label originally associated with 2,4,5-T was shown to be secreted by the renal tubule. Probenecid inhibited the transport of the 14C-label without affecting the simultaneous transport of tetra-ethylammonium, an organic cation transported by the renal proximal tubule. At the present infusion rate of 2,4,5-T (2.9 X 10(-10) mol/min), the excreted label was associated primarily with an acidic metabolite(s). It can be concluded that the chicken transports 2,4,5-T by a probenecid sensitive mechanism; however, this transport appears to be associated with the metabolism of the herbicide.