Experimental study on the mechanism of hepatic injury following halothane anesthesia

Part 2. Changes in hepatic microsomal enzymes

Abstract

Using male rats pretreated with phenobarbital (PB), fasted, and then exposed to 0.7% halothane at 10% or 100% oxygen, the content and activity of hepatic microsomal enzymes were measured. The content of cytochrome b₅ and the activity of NADPH-cytochrome P-450 reductase were increased by PB-pretreatment, but not changed by exposure to halothane at 10% or 100% oxygen. Although the content of cytochrome P-450 (P-450) and the activity of aminopyrine demethylation were increased by PB-pretreatment and decreased by exposure to halothane at 10% oxygen, aniline hydroxylation activity was decreased by PB-pretreatment and not changed by exposure to halothane. These results suggested that the subtypes of P-450 which were increased by PB-pretreatment were decreased by exposure to halothane at 10% oxygen. A close relationship may exist between the decreases in content of P-450 and the development of hepatic injury following halothane anesthesia in rat.