EFFECT OF THE HERBICIDE 2,4-DICHLOROPHENOXYACETIC ACID (2,4-D) ON THEENERGY-METABOLISM OF RAT RENAL CORTICAL MITOCHONDRIA

2,4-Dichlorophenoxyacetic acid (2,4-D) depresses the phosphorylation e fficiency of rat renal cortical mitochondria, as deduced from the decr ease of respiratory control (RCR) and ADP/O ratios when NAD(+) -depend ent substrates were used. The amplitude and the velocity of swelling i nduced by glutamate was progressively inhibited, while with succinate and TMPD + ascorbate as substrates a partial inhibition of the amplitu de was observed. Shrinkage was not compromized. 2,4-D promotes complet e (2-oxoglutarate) and partial (succinate or ATP) inhibitions of the t ransmembrane potential. These results characterize an interaction of 2 ,4-D with complex I of the respiratory chain without effect on the ela sticity of the inner mitochondrial membrane.