Acetaldehyde level in the blood and liver aldehyde dehydrogenase activities in trichloroethylene-treated rats.

The liver NAD+-dependent aldehyde dehydrogenase (AldDH) activity and the acetaldehyde level in the blood during ethanol metabolism after trichloroethylene (trichlene) exposure were studied in rats. Trichlene inhalation caused large elevations in acetaldehyde levels during ethanol metabolism and caused decreases in the activity of the AldDH with a low Km value in mitochondrial and soluble fractions of liver cells. No significant effects were found in the activity of the high Km-enzyme in mitochondrial, soluble and microsomal fractions. Time course of inhibition of the mitochondrial low Km-enzyme and that of elevations in acetaldehyde levels during ethanol metabolism after trichlene exposure were similar. These findings suggest that acetaldehyde formed from ethanol in vivo is oxidized primarily by the mitochondrial low Km-enzyme.