Induction of inflammation in rats by treatment with endotoxin or turpentine is known to suppress levels of hepatic mRNAs for P450IIC11 and P450IIC12. We report that transcription of CYP2C12 in female rats is not significantly reduced from control levels; suppression of this gene during inflammation appears to be mediated post-transcriptionally. In contrast, transcription of CYP2C11 in male rats is reduced to 23% and to 5% of control levels by turpentine and by endotoxin, respectively. Sex-specificity of CYP2C11 expression is also regulated transcriptionally, whereas sex-specificity of CYP2C12 expression appears to be regulated by a post-transcriptional mechanism.