Aspartate Aminotransferase (AST)

AST is widely distributed throughout the tissues, with significant amounts in the heart and liver. Lesser amounts are found in skeletal muscles, kidneys, pancreas, spleen, lungs, and brain. Injury to these tissues results in releasing the AST enzyme into general circulation. In myocardial infarction, serum AST may begin to rise within 6-8 hours after onset, peak within two days, and return to normal by the fourth or fifth-day post infarction. Increased serum AST is also found with hepatitis, liver necrosis, cirrhosis, and liver metastasis.