[Gamma-glutamyltransferase. Human pathology and animal biology]

Gamma-glutamyltransferase (GGT, EC 2.3.2.2) is in man and animals mainly a renal enzyme. It is also present in non-negligeable quantities in the liver except in certain rodents such as the rat. In the cells, the cytosoluble fraction of the enzyme is very low and most of the enzyme is linked to the microsomal fraction in vitro. This fraction permits its use in the diagnosis of liver and biliary disease by measurement of its serum activity and that of renal disease by measurement of its urinary activity. In biological research, the prospects offered by GGT both in human and animal cancers, and in pharmacology and toxicology makes it probably one of the most appreciated biological tests in the exploration of liver, biliary and renal function.