N-acetyl LTE4 is the major inactive metabolite of LTE4 found in bile. This route of metabolism is prominent in the rat, but of minor importance in humans.{544,546} N-acetyl LTE4 is 100 times less potent than LTC4 as a vasoconstricting agent.{546} In healthy human subjects urinary excretion of N-acetyl LTE4 is about 1.5 nmol/mol creatinine, which is considerably less than that of LTE4 (12 nmol/mol creatinine).{307}