Abstract |
Three chlorinated methanes, carbon tetrachloride, chloroform and methylene chloride known to cause liver tumors in rodents, were given by oral gavage to adult female rats both 21 and 4 hours before sacrifice. Then hepatic DNA damage, ornithine decarboxylase, cytochrome P-450, glutathione content and serum alanine aminotransferase activity assays were performed. Carbon tetrachloride increased rat hepatic ornithine decarboxylase activity and decreased cytochrome P-450 content at doses both below and above cytotoxicity (as measured by increased serum alanine aminotransferase activity). At 54 and 160 mg/kg, chloroform increased hepatic ornithine decarboxylase activity with minimal or no elevation in serum alanine aminotransferase activity. After oral administration of 480 mg/kg of chloroform, hepatic ornithine decarboxylase activity, serum alanine aminotransferase activity and hepatic DNA damage were increased while hepatic cytochrome P-450 content was decreased. The results with methylene chloride varied between replicates done on three different days. (Copyright (c) 1989 Alan R. Liss, Inc.) |