Expansion
Synthesis, storage, metabolism, detoxification, excretion and immune function
Expansion
- Synthesis: albumin, clotting factors (all except factor VIII and von Willebrand factor), complement, transport proteins, bile salts
- Storage: glycogen, vitamins A, D, B12 and K, iron and copper
- Metabolism: glucose homeostasis through glycogenolysis and gluconeogenesis, lipid and lipoprotein metabolism, protein deamination and the urea cycle
- Detoxification: phase I (cytochrome P450 oxidation) and phase II (conjugation) reactions; first-pass metabolism
- Excretion: bilirubin, cholesterol, drugs, hormones
- Immune: Kupffer cells filtering portal blood
Failure of each explains a clinical feature: hypoalbuminaemia gives oedema, loss of clotting factors gives a raised prothrombin time, failed ammonia handling gives encephalopathy, failed bilirubin excretion gives jaundice, failed hormone metabolism gives gynaecomastia and spider naevi, and failed detoxification alters drug handling.
Factor VIII is the exception among clotting factors, being made by endothelium, which is why it is normal or high in liver disease but low in disseminated intravascular coagulation.