AST is not liver specific and is found in most tissues. Activity is relatively high in liver, skeletal and cardiac muscle. Significant increases may occur with liver or muscle damage or with haemolysis (in vitro or delayed removal of serum from a clot may cause mild to moderate increases). It is found in the cytosol and mitochondria of hepatocytes and is released into the blood due to hepatocellular damage and necrosis. In liver disease increases in AST usually parallel ALT. Therefore elevated AST and CK with normal ALT are more suggestive of muscle damage. There is no real advantage in measuring AST rather than ALT. The half life is about 12 hours in the dog, less in cats and 7 to 8 days in horses. | AST is not liver specific and is found in most tissues. Activity is relatively high in liver, skeletal and cardiac muscle. Significant increases may occur with liver or muscle damage or with haemolysis (in vitro or delayed removal of serum from a clot may cause mild to moderate increases). It is found in the cytosol and mitochondria of hepatocytes and is released into the blood due to hepatocellular damage and necrosis. In liver disease increases in AST usually parallel ALT. Therefore elevated AST and CK with normal ALT are more suggestive of muscle damage. There is no real advantage in measuring AST rather than ALT. The half life is about 12 hours in the dog, less in cats and 7 to 8 days in horses. |