This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
VMA is a metabolite of: 
Select and explain. 
A. Adrenaline, B. Thyroxine, C. Serotonin, D. Growth hormone
A: Adrenaline
Answer: A: Adrenaline 
Explanation: Ans: a (Adrenaline) Ref: Vasudevan, 4th ed, p. 190; 5th ed, p. 205Epinephrine is metabolised by COMT and MAO; the end product is VMA.NorepinephrineBridge to PharmacologyNon selective MAO inhibitors :Phenelzine, tranyl cypromine, Iso carboxyzine.||EpinephrineSelective MAO inhibitorMAO-I Type A:mainly in liver. But anywhere (metabolises NE, 5HT, and tyramine)E.g.: clorgyline, meclobemideMAO-I Type B:mainly in brain, metabolises DA, PhenylethylamineE.g.: Selegeline, deprenylCOMTMetanephrineMAOVMA