Biotransformation, sex hormones, and toxicity of two volatile anesthetics in mice.

Male and female DBA 11 mice recovered from 1 hr of anesthesia with chloroform of fluoroxene apparently unharmed. However, many of the animals died within 24-48 hr after anesthesia. Pretreatment with phenobarbital increased, while pretreatment with a small dose of carbon tetrachloride decreased, this toxicity. Relatively more males than females died. Pretreatment with estradiol in males and testosterone in females reversed this ratio. We conclude that the murine toxicity of chloroform and fluoxene is dependent on biotransformation by hepatic microsomal enzymes and that the testosterone enhances postanesthetic toxicity of these agents.