SPECIFICITY OF ENZYME INHIBITION BY DDD.

Summary Dog adrenal glucoses-phosphate dehydrogenase is inhibited by DDD feeding while the same enzyme is not changed in the adrenals of similarly treated rats. The activity of the liver enzyme is not affected in either species. Inhibition of neither purified yeast G-6-PDH, normal liver, nor adrenal enzyme could be demonstrated after addition of DDD to incubation mixtures. DDD feeding does not decrease the activity of 6-phosphogluconate dehydrogenase in the liver or adrenal of either species. No effect of DDD on dog liver Cortisol reductase could be demonstrated. Direct evidence for lack of effect of this drug on rat adrenal steroid secretion rate is presented.