In vivo protection by protein A of hepatic microsomal mixed function oxidase system of CCl4-administered rats.

The in vivo protection by protein A of hepatic mixed function oxidase system of carbon tetrachloride (CCl4) administered rats, has been investigated in the present communication. Aryl hydrocarbon hydroxylase activity was decreased by 63% in CCl4 administered rats while in protein A + CCl4 administered rats the decrease was in the range of 22-25% (group IV-V). The aryl hydrocarbon hydroxylase activity in protein A + CCl4 administered rats showed significant increase in group IV (P less than 0.005) and group V (P less than 0.001) in comparison to CCl4 alone (group II). Similarly, aniline hydroxylase and aminopyrene N-demethylase were decreased, by 75 and 84% respectively in CCl4 administered rats and 31% and 54-64%, respectively in protein A + CCl4 administered rats (groups IV and V). The aniline hydroxylase activity was also found enhanced in protein A + CCl4 administered group IV and V (P less than 0.001). In addition the aminopyrene N-demethylase also showed significant increase in its activity in group IV (P less than 0.001) and group V (P less than 0.001) in comparison to CCl4 alone. In accordance with these data, serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase exhibited significantly less increase in their activity in animals receiving protein A and CCl4 than those treated with CCl4 alone. Protein A alone was found to have no effect on any of these enzymes. Our results indicate that protein A protects CCl4 induced injury as judged by the biochemical alterations and suggests that it may be useful in providing an excellent system for the investigation on the regeneration of the hepatic enzyme activity following toxic insult of CCl4.