Notes: Ophthalmic acid is a glutathione (GSH) analog and biomarker of hepatic glutathione depletion.{68062} It is formed via the GSH synthesis pathway, substituting 2-aminobutyrate for cysteine. Plasma and hepatic levels of ophthalmic acid are increased in fasted mice and in a mouse model of acetaminophen-induced hepatotoxicity.{68062,68063}