<prompt> Enzyme specifically raised in chronic alcoholics: September 2009Gamma-glutamyl transferase GGTAlanine aminotransferase ALTAspaate aminotransferase ASTRatio of AST: ALT  <response>: Ans. D: Ratio of AST: ALT Transferases - Alanine aminotransferase ALT or Aspaate aminotransferase AST: These enzymes normally reside inside cells in cytoplasm so raised levels usually represent hepatocellular damage. ALT is more specific to the liver, as AST is also found in cardiac and skeletal muscle and red blood cells. Very high levels 1000 IU1 suggest drug induced hepatitis e.g. paracetamol, acute viral hepatitis A or B , ischaemic or rarely autoimmune hepatitis. The ratio of AST to ALT can give some extra clues as to the cause: In chronic liver disease ALT AST, once cirrhosis established AST ALT. The extremes of the ratio of AST:ALT can also be helpful: 2 suggests alcoholic liver disease, and a ratio of Gamma-glutamyl transferase GGT - also related to the bile ducts. Typically elevated in cholestasis with elevated ALP, but if ALP normal suggests induction of hepatic metabolic enzymes e.g alcohol or enzyme inducing drugs. It is not specific to alcohol, easily inducible and is elevated in all forms of fatty liver. Alkaline phosphatase ALP - comes mainly from the cells lining bile ducts but also in bone. Marked elevation is typical of cholestasis often with elevated GGT or bone disorders usually normal GGT. Isoenzymes analysis may help identify source. It is physiologically increased when there is increased bone turnover e.g. adolescence and is elevated in the third trimester produced by the placenta. 