The effect of benzpyrene, phenobarbital, and carbon tetrachloride on subcellular metal distribution and microsomal enzyme activity.
Normal subcellular metal distribution of rat liver and lung is altered by acute administration of phenobarbital, carbon- tetrachloride, and intratracheal 3,4-benzpyrene. Following the isolation of the various subcellular fractions by a standard technique, the metal composition of the subfractions was determined by atomic absorption spectrophotometry and expressed as micrograms metal per milligrams nitrogen. Significant increases in lung microsomal copper and significant decreases in microsomal nickel and chromium were observed 72 hours after intratracheal administration of 3,4-benzpyrene hydroxylase activity. The administration of phenobarbital (75 mg/kg) to rats for 3 days produced significant increases in liver microsomal copper, manganese, and zinc levels. In contrast, the administration of a subacute dose of carbon- tetrachloride (0.5 ml/kg) produced a significant reduction of liver microsomal copper, manganese, and zinc, as well as a marked depression of liver aniline hydroxylase activity. The subcellular metal changes may reflect a redistribution of endogenous metal stores in the enzyme responsive tissue, since they cannot be explained by alterations in the whole organ metal content or the nitrogen content of the subfractions.