Induced tolerance to acrylonitrile toxicity by prior acrylonitrile exposure

Pretreatment by inhalation with sublethal concentrations of acrylonitrile protects rats from subsequent, normally lethal, ACN exposures. However, inhalation-induced tolerance to ACN does not protect against subsequent poisoning by cyanide. Metabolic liberation of cyanide has been suggested to be responsible for the toxicity of ACN. Protection against ACN toxicity is not provided by pretreatment with compounds which have structural similarity to ACN, i.e. acrylamide or ethylene, nor by cyanide per se. Enzyme induction with Aroclor 1254 also does not protect against ACN toxicity. The latter data suggest that the tolerance resulting from ACN pretreatment is not the result of enzyme induction and the basis for the protective effect of ACN inhalation pretreatment remains unclear.