Alanine aminotransferase (ALT) also known as glutamate pyruvate transaminase (GPT) is a transaminase. ALT catalyses the transfer of the amino group of L-alanine to α-ketoglutarate to give L-glutamate. The highest levels are found in the liver and the kidneys,
and in smaller amounts in heart and skeletal muscle.
ALT concentration is increased when hepatic cells are damaged (liver cell necrosis or injury of any cause). Indeed, viral and toxic
hepatitis induce a marked elevation of ALT activity in serum. Intake of alcohol, delirium tremens, and administration of various drug
induce slight or moderate elevation of ALT. ALT concentration in serum is also slightly increased in various conditions such as : muscular dystrophy, hemolytic disease, myocardial infarction…
ALT is more liver specific than AST (Aspartate aminotransferase). Measurement of both AST and ALT has some value in distinguishing hepatitis from other parenchymal lesions.
ALT serum level can decrease in case of vitamin B6 deficiency.