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[Biochemistry](https://durgical.com/en/biochemistry/) · Topic

# 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.

## In detail

- 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.

**Also called**
Lactic acid cycle

## Clinical notes

- 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.

## Pathways

- [Gluconeogenesis](https://durgical.com/en/biochemistry/pathways/gluconeogenesis/)
- [Glycolysis](https://durgical.com/en/biochemistry/pathways/glycolysis/)

## Related conditions

- [Lactic acidosis](https://durgical.com/en/conditions/lactic-acidosis/)
- [Von Gierke disease (glycogen storage disease type I)](https://durgical.com/en/conditions/von-gierke-disease/)
- [Cirrhosis](https://durgical.com/en/conditions/cirrhosis/)
- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)

## Related

- [Lactate](https://durgical.com/en/biochemistry/molecules/lactate/)
- [Pyruvate](https://durgical.com/en/biochemistry/molecules/pyruvate/)
- [Glucose](https://durgical.com/en/biochemistry/molecules/glucose/)
- [Glucose–alanine cycle](https://durgical.com/en/biochemistry/topics/glucose-alanine-cycle/)
- [NAD⁺ (nicotinamide adenine dinucleotide)](https://durgical.com/en/biochemistry/molecules/nad/)

## Test yourself

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.

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

Sources: [Gluconeogenesis](https://reactome.org/PathwayBrowser/#/R-HSA-70263) (Reactome, 2026); [Glycolysis](https://reactome.org/PathwayBrowser/#/R-HSA-70171) (Reactome, 2026); [LDHA: L-lactate dehydrogenase A chain (human)](https://www.uniprot.org/uniprotkb/P00338/entry) (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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