Biochemistry · Molecule
Adrenaline !
The adrenal medulla hormone for acute stress: it raises glucose and fatty acids and speeds up the heart.
Updated 2026-11-01
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Key facts
- PNMT makes it in the adrenal medulla from noradrenaline; PNMT depends on cortisol.
- Receptors: β1 (heart), β2 (bronchi, liver, muscle) and β3 (fat) through Gs/cAMP; α1 through Gq/IP₃; α2 through Gi.
- Metabolic effects: glycogenolysis in liver and muscle, lipolysis, more glucagon and less insulin (α2 on the beta cell).
- COMT and MAO break it down to metanephrine and vanillylmandelic acid.
- Also called
- Epinephrine
- Formula
- C9H13NO3
- PubChem
- CID 5816
Structure
- A catechol (ring with two hydroxyls) joined to an ethanolamine chain with a methyl group on the nitrogen.
- That methyl, added by PNMT, is what sets it apart from noradrenaline.
Clinical notes
- It is the first-line treatment for anaphylaxis.
- Phaeochromocytoma secretes too much: hypertensive crises, hyperglycaemia and high metanephrines.
- It is one of the first counter-regulatory hormones in hypoglycaemia; beta-blockers can mask the tremor and palpitations.
Pathways
Related conditions
Related
- Catecholamines: synthesis and breakdown
- Tyrosine
- G protein-coupled receptors and cAMP
- IP₃, DAG and calcium pathway
- Glycogen phosphorylase
- Hormone-sensitive lipase (HSL)
- Cortisol
- Exercise metabolism
Test yourself
Think of the answer, then tap the question to see it.
Which enzyme turns noradrenaline into adrenaline, and which hormone induces it?
PNMT, induced by cortisol arriving from the adrenal cortex.
Why does adrenaline, unlike glucagon, mobilise muscle glycogen?
Because muscle has β2-adrenergic receptors and no glucagon receptors.
How does adrenaline lower insulin secretion?
Through Gi-coupled α2 receptors on the beta cell, which lower cAMP.
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: Epinephrine (CID 5816) (PubChem, NCBI, 2026) · Public domain; Catecholamine blood test: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); PNMT: Phenylethanolamine N-methyltransferase (human) (UniProt, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).
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Representative model, for educational purposes only.