Norepinephrine (noradrenaline) !

Norepinephrine is the transmitter of sympathetic nerves and a hormone of the adrenal medulla. It raises blood pressure and alertness.

Updated 2026-11-01

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Key facts

Made from dopamine by dopamine β-hydroxylase inside storage vesicles.
Released by postganglionic sympathetic neurons; it acts mostly on α₁, α₂ and β₁ receptors.
PNMT methylates it to epinephrine in the adrenal medulla.
Its main breakdown products are normetanephrine and VMA.

Dopamine with a hydroxyl on the β carbon of the side chain; a primary amine (epinephrine has an extra N-methyl).

It is a first-line vasopressor in septic shock.
Plasma normetanephrine is the most sensitive marker of norepinephrine-secreting phaeochromocytomas.
Cocaine and tricyclic antidepressants block its reuptake.

Think of the answer, then tap the question to see it.

Which enzyme turns norepinephrine into epinephrine, and where?

PNMT, using SAM, mainly in the adrenal medulla.

Which receptors does norepinephrine mainly act on?

α₁, α₂ and β₁; it has little effect on β₂ receptors.

Which metabolite is measured for norepinephrine-secreting tumours?

Normetanephrine, made by COMT, in plasma or urine.

Molecules are shown in their neutral form, as the databases deposit them; in the cell the acids and phosphates are ionised.

Educational information, not medical advice. For any symptom, see a health professional.

Sources: Norepinephrine (CID 439260) (PubChem, NCBI, 2026) · Public domain; Dopamine beta-hydroxylase deficiency: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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