The effect of 4-methyltropolone on the metabolism of adrenaline.

The inhibiting effects of 4-methyltropolone have been tested in a partially purified preparation of O-methyltransferase from rat liver. The inhibition observed was of a strictly competitive nature whether the enzyme was or was not preincubated with the inhibitor. Addition of the substrate partially reversed the inhibition.The injection of C14-labelled adrenaline in rats pretreated with 4-methyltropolone (30 mg/kg) clearly indicated a decreased excretion of labelled metanephrine.