In vivo covalent binding of trans-4-hydroxy-2-hexenal to rat liver macromolecules

Trans-4-hydroxy-2-hexenal (t-4HH), a metabolite isolated from the macrocyclic pyrrolizidine alkaloid senecionine, was tritiated to perform in vivo covalent binding studies. The in vivo binding of [3H]t-4HH to rat liver DNA, RNA and protein was investigated. No significant binding to hepatic DNA or RNA could be detected, but levels of 429 +/- 139 pmol/mg were found covalently bound to hepatic proteins 16 h after exposure. Levels as high as 916 pmol/mg protein were detected 2 h after administration of [3H]t-4HH via the hepatic portal.