Toxicity and biotransformation of volatile halogenated anesthetics in rat hepatocyte suspensions

This study examines the toxicity (as measured by reduced intracellular K+) and metabolism (defluorination) of halothane and enflurane in rat hepatocytes in suspension (RHS) with regards to O2 tension, time, and concentration. In 95% O2 halothane is more toxic than enflurane when RHS are exposed to 5-20 microliters of these anesthetics. At these levels halothane is not metabolized while enflurane is metabolized. At 21% O2 a similar pattern was seen with regards to toxicity. However, metabolism of halothane rapidly reached an elevated level while that of enflurane is reduced when compared to 95% O2. Thus toxicity of halothane and enflurane at these dose levels appears to be unrelated to metabolism and due solely to a solvent effect.