Studying the relationship of liver transaminases and alkaline phosphatase with the activity of gammaglutamyltransferase in horses

Abstract

This article presents the results of a comparison of the activity of indicator enzymes of the hepatobiliary system in horses - alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) with the activity of gamma-glutamyltransferase (GGT). The results of a biochemical blood test were grouped according to the activity of gamma-glutamyltransferase and, in connection with this, 4 groups were formed with an enzyme activity step of 10 IU/l. When conducting a correlation analysis, a strong positive relationship was revealed between the level of GGT and AST (r = 0.97) and ALP (r = 0.88), and when comparing GGT and ALT, a moderate positive relationship was found (r = 0.64). The absence of natural changes in ALT activity with increasing GGT is explained by the induction of the enzyme to ensure the optimal rate of transamination in metabolic reactions, and not a consequence of liver pathology. A statistically significant increase in AST and ALP activity was found in the group with GGT activity exceeding standard limits, compared with the minimum values by 59.1% and 29.7%, respectively (P<0.05). An increase in GGT activity above the upper limit of the reference limits is accompanied by a significant increase in aspartate aminotransferase and alkaline phosphatase levels, which indicates the presence of pathology of the hepatobiliary system involving both the liver parenchyma and the biliary tract.