3,4-Dihydroxyphenylglycolaldehyde (DOPEGAL), also known as 3,4-dihydroxymandelaldehyde (DHMAL) as well as norepinephrine aldehyde or epinephrine aldehyde, is a metabolite of the monoamine neurotransmitters norepinephrine and epinephrine. DOPEGAL is a noradrenergic neurotoxin.
DOPEGAL is formed by monoamine oxidase (MAO) via oxidative deamination. Following its formation, DOPEGAL is metabolized. Through the metabolism process, it is converted into 3,4-dihydroxymandelic acid (DHMA) via aldehyde dehydrogenase (ALDH), or into 3,4-dihydroxyphenylglycol (DHPG) via aldehyde reductase (ALR).