Metabolism of Zearalenone in Rat Liver

Abstract

The metabolism of zearalenone, a fungal crop contaminant which constitutes a risk to domestic animals, in rat liver is investigated. The studies were performed mainly with liver homogenate, though isolated microsomes and hepatocytes were also used. Zearalenone was metabolized along 2 principal pathways, conjugation with glucuronic acid, which was the main route and reduction to an isomer of zearalenol. In no case could all zearalenone metabolized be accounted for as conjugated zearalenone and free and conjugated zearalenol. Another unknown metabolite cannot be excluded. Reduction to zearalenol could be increased 2 .times. by the addition of NADH (or NADPH) and is probably catalyzed by a hydroxysteroid dehydrogenase. Some 25-50% of the zearalenol could be conjugated, depending on the incubation conditions. The capacity of hepatocytes to eliminate zearalenone was about 100 .mu.g/g of liver in 1 h. With a liver homogenate the highest value obtained was 82 .mu.g.