Two routes of acrylonitrile metabolism.

Acrylonitrile (AN) is metabolized in two different routes. The minor route of AN metabolism is its conversion to cyanide. In vitro experiments confirmed that this biotransformation proceeds via glycidonitrile (catalyzed by hepatic monooxygenases) and glycolaldehyde cyanohydrin (catalyzed by epoxide hydrase).

New findings on acrylonitrile metabolism.

The mechanism of the metabolic pathway of acrylonitrile to cyanide (and subsequently to thiocyanate which is excreted in the urine) was already previously confirmed by our work in vitro as well as in vivo. This metabolic route of AN via glycidonitrile and glycolaldehyde cyanohydrin is not the dominant pathway in the total balance of AN metabolism and does not elucidate the fate of the predominant amount of AN. By means of AN labelled with 14C on the nitrile group it was confirmed that, when different routes of administration are used, AN forms in the rat the main portion of radioactivity excreted in the urine in "non-thiocyanate" metabolites.

Acrylonitrile metabolism in the rat.

Acrylonitrile (AN) is metabolized by an oxidative pathway via glycidonitrile and glycolaldehyde cyanohydrin to cyanide (CN-), which is transformed to thiocyanate. The major route of AN metabolism (more than 2/3), however, proceeds via cyanoethylation of glutathione, to N-acetyl-S-(2-cyanoethyl)cysteine (AN-mercapturic acid) as a final product.