Catecholamines

Catecholamines are a family of closely related signaling molecules that includes dopamine, norepinephrine, and epinephrine. They are synthesized from the amino acid tyrosine and act as neurotransmitters, hormones, or both depending on where they are released. Their shared chemical structure contains a catechol ring and an amine group, which is the basis of the family name .^1,2

Norepinephrine is an important transmitter in the sympathetic nervous system and in several brain pathways, while epinephrine is released prominently from the adrenal medulla into the bloodstream. Dopamine has major functions in the brain and is also the biochemical precursor from which norepinephrine and epinephrine are made. Together, catecholamines help coordinate rapid responses involving cardiovascular function, attention, arousal, metabolism, and adaptation to physical or psychological stress .¹

The term catecholamine describes the chemical and biosynthetic family, not one single stress hormone. Different catecholamines bind different patterns of adrenergic or dopaminergic receptors and can therefore produce different effects across tissues. Their concentrations can rise during exercise or acute stress, but the size and meaning of that rise depend on the specific catecholamine, the stimulus, the sampled compartment, and timing .^1,2