Absorption and metabolism of the mycotoxin zearalenone and the growth promotor zeranol in Caco-2 cells in vitro.

Scope: Zearalenone (ZEN) and α-zearalanol (α-ZAL, zeranol) were studied in differentiated Caco-2 cells and in the Caco-2 Millicell® system in vitro to simulate their in vivo intestinal absorption and metabolism in humans.

Methods And Results: In addition to metabolic reduction/oxidation, extensive conjugation with glucuronic acid and sulfate of the parent compounds and their phase I metabolites was observed. The positional isomers of the glucuronides and sulfates were unambiguously identified: Sulfonation occurred specifically at the 14-hydroxyl group, whereas glucuronidation was less specific and, in addition to the preferred 14-hydroxyl group, involved the 16- and 7-hydroxyl groups.