9-OxoODE, formed through the oxidation of the allylic hydroxyl group in both 9(S)-HODE and 9(R)-HODE, is present in rabbit reticulocyte plasma and mitochondrial membranes as both 9- and 13-oxoODEs, constituting approximately 2% of the total linoleate residues. The majority of these oxidized linoleate residues are esterified to membrane lipids.