The in Vivo Toxicity of CS2 to Liver Microsomes: Binding of Labelled CS2 and Changes of the Microsomal Enzyme Activities

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Abstract
The binding of 35S and 14C labeled CS2 to liver microsomes was studied in control and phenobarbitone pretreated rats 3 and 6 h after an i.p. injection. The level of hepatic cytochrome P-450, the activities of epoxide hydratase and UDP-glucuronosyltransferase were analyzed in the same animals. The binding of the S label was considerably higher than that of C 3 h after the injection, the difference being less evident at 6 h. The measurable P-450 declined after the CS2 injection. It was approximately 40% in the phenobarbitone pretreated rats and 60% in control rats of the values of animals which were not treated with CS2. CS2 did not affect microsomal epoxide hydratase activity, white it increased the measurable activity of UDP-glucuronosyltransferase. The increase was evident 3 h after the injection of CS2 in the phenobarbitone pretreated rats. It could also be detected in the control animals 6 h after the injection. The change in the measurable P-450 possibly results from the binding of the metabolite(s) of CS2 to the cytochrome, and its subsequent degradation. The increase in measurable UDP-glucuronosyltransferase activity results probably from the activated perturbation of the structure of microsomal membrane by the metabolites of CS2 in vivo. [CS2 is a toxin in industrial environments.].