Cori cycle !

In the Cori cycle, lactate made by muscle and red cells travels to the liver, is turned back into glucose and returns to the blood.

Updated 2026-11-01

Key facts

Working muscle and red cells: glucose → 2 lactate, gaining 2 ATP.
Liver: 2 lactate → glucose by gluconeogenesis, at a cost of 6 high-energy bonds.
Net balance: the body spends 4 ATP per turn; the liver pays with fatty acid oxidation.
It recycles lactate carbon and keeps it from accumulating.

1. In a muscle fibre short of oxygen, or in a red cell with no mitochondria, glycolysis produces pyruvate and NADH.
2. Lactate dehydrogenase reduces pyruvate to lactate and regenerates the NAD⁺ that glycolysis needs.
3. Lactate leaves into the blood through monocarboxylate transporters and reaches the liver.
4. In the hepatocyte lactate dehydrogenase oxidises it back to pyruvate.
5. Pyruvate goes through gluconeogenesis (pyruvate carboxylase, PEPCK… glucose-6-phosphatase) and leaves as glucose.
6. Glucose returns to muscle and red cells and the cycle closes.

If the liver fails (cirrhosis, shock) or perfusion is poor, lactate is not recycled and lactic acidosis appears.
Metformin and alcohol slow hepatic gluconeogenesis and can raise lactate.
In GSD I the liver cannot close the cycle (no glucose-6-phosphatase) and lactate is high.

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

Between which organs does the Cori cycle run?

Between muscle (and red cells), which make lactate, and the liver, which turns it into glucose.

How much energy does one turn of the Cori cycle cost?

Net 4 ATP: glycolysis gives 2 and gluconeogenesis spends the equivalent of 6.

Why can liver failure cause lactic acidosis?

The liver stops turning lactate into glucose and lactate builds up.

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

Sources: Gluconeogenesis (Reactome, 2026); Glycolysis (Reactome, 2026); LDHA: L-lactate dehydrogenase A chain (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.