Fasting Enhances the Acute Toxicity of Acrylonitrile in Mice via Induction of CYP2E1.

Cytochrome P450 2E1 (CYP2E1) plays an essential role in the susceptibility to acute acrylonitrile (AN)-induced toxicity. Here, we investigated the toxicity and mechanism of AN in fasting mice and potential underlying mechanisms. Convulsions, loss of righting reflex, and death 4 h after AN treatment were observed and recorded for each group of mice. Relative to ad lib-fed mice, 48 h fasting significantly increased the acute toxicity of AN, as noted by a more rapid onset of convulsions and death. In addition, fasting significantly enhanced CYP2E1-mediated oxidative metabolism of AN, resulting in increased formation of CN (one of the end-metabolites of AN). Moreover, fasting decreased hepatic GSH content, abrogating the detoxification of GSH. However, trans-1,2-dichloroethylene (DCE), a CYP2E1 inhibitor, altered the level of hepatic CYP2E1 activity in response to fasting, reduced the acute toxic symptoms of AN and the content of CN in AN-treated mice. These data establish that fasting predisposes to AN toxicity, attributable to induced CYP2E1 and reduced hepatic GSH.