The N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) a N1-acetyl-5-methoxy-kynuramine (AMK) pathways of melatonin metabolism were investigated both in mice and humans. Metabolomic analysis did identify novel metabolites of AMK, i.e. hydroxy-AMK and glucuronide-conjugated hydroxy-AMK only in mice.
These data suggest that AFMK/AMK formation is not a significant pathway of melatonin disposition in mice.