<prompt> HIAA is a metabolite of:SerotoninDopamineEpinophrineHistamine  <response>: Ans is a i.e. SerotoninSerotonin or 5 hydroxytryptamine is catabolized to 5 Hydroxy indole acetic acid 5HIAA.The enzyme which catalyzes this reaction is - Monoamine oxidase.5 HIAA is excreted normally in urine. Normal adult excretes about 7 mg of HIAA per day. 