The effect of adrenaline on human platelet MAO activity.

Platelet monoamine oxidase (MAO) activity was determined before and after the subcutaneous administration of adrenaline to nine healthy volunteers. Significant increases were found 15 min and 1 hr after adrenaline in the enzymatic activity with benzylamine acting as substrate. Increases were also found in all but two samples in the activity towards tyramine. Such increases may be part of a general response to "stress", and, if so, need to be taken into account when interpreting changes in platelet MAO activity in psychiatric patients.