Rat liver aldehyde dehydrogenases: strain differences in the response of the enzymes to phenobarbital treatment.

The effect of phenobarbital on activities of aldehyde dehydrogenases in the subcellular fractions was studied in vivo in rats of three strains. Regarding the responses of the mitochondrial and microsomal enzymes to phenobarbital treatment no difference among the strains was observed. Regarding the responses of the supernatant enzyme remarkable strain differences were observed. In rats of the Long-Evans strain the high Km-enzyme activity increased as much as 15-fold above control levels by phenobarbital treatment. By contrast, in rats of the Wistar strain the high Km-enzyme activity was unchanged in all rats by treatment with phenobarbital. In rats of the Sprague-Dawley strain the high Km-enzyme activity remained unchanged in 52% of all rats treated with phenobarbital and was increased approximately 4-fold over control levels in 48% of treated rats.