Hepatic protection from chemical injury by isoflurane

Isoflurane inhibits oxidative metabolism of halothane. Because hepatotoxicity of chemicals may be associated with their metabolism, whether isoflurane can protect the liver against chemical injury was investigated. Hepatic injury was produced in female F344 rats by a 30-minute exposure to 250 ppm of carbon tetrachloride. In this and all other parts of the study, the inspired oxygen concentration was maintained at 21%. The injury was accompanied by elevated activity of liver enzymes in serum (SGOT, SGPT, and SDH), enlarged liver, fatty infiltration of the liver, and vacuolar degeneration of hepatocytes. These signs of toxicity were partly or completely suppressed by concurrent exposure to subanesthetic concentrations of isoflurane (0.2 or 0.038%, respectively). The protective effect was concentration-dependent. Enflurane was protective, but less so than isoflurane. Nitrous oxide and fentanyl had no protective effect.