Lactate Dehydrogenase Activity: Effect in vitro of Some Pesticidal Chemicals
Carl R. Sova 1
1 Southwest Water Laboratory, Federal Water Pollution Control Administration, Athens, Georgia
The effect of chlorinated hydrocarbon insecticides upon rabbitmuscle lactate dehydrogenase was determined by both the direct determination of diphosphopyridine nucleotide reduction and a tetrazolium salt reduction method. A comparison of the two assay procedures revealed that the pronounced stimulation of lactate dehydrogenase LDH activity was noted with the tetrazolium salt method but could not be detected with a direct photometric determination method. Incubation of lactate dehydrogenase with DDT or heptachlor prior to the addition of either diphosphopyridine nucleotide or substrate resulted in a complete inhibition of enzyme activity. The inclusion of either diphosphopyridine nucleotide or substrate in the prior incubation mixtures afforded no protection to the enzyme.
