Changes in indicators of hepatocellular damage and cholestasis in connection with bilirubin level in horses

The article describes the results of a study in the blood of horses of hepatospecific markers – the enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT), which were ranked by bilirubin concentration. The conducted studies revealed the relative constancy of enzymes – markers of hepatocellular damage and cholestasis in the ranges of bilirubin values from 5.9 to 20.0 mmol/L. At a bilirubin concentration from 20.0 to 25.0 mmol/l, there are signs of an increase in the activity of all the studied enzymes, but the changes are not statistically significant. At bilirubin concentrations from 30.0 to 48.3 mmol/l, there was a significant increase in ALT by 46.4%, AST by 20.4% and GGT by 36.0%. Correlation analysis of the studied enzymes against the background of hyperbilirubinemia showed the presence of a strong positive relationship between the enzymes markers of cytolysis ALT and AST (Pearson coefficient r=0,89) and between the enzymes markers of cholestasis GGT and alkaline phosphatase (Pearson coefficient r=0,72). It was found, that unidirectional changes are observed only in either markers of hepatocyte cytolysis or markers of cholestasis. A significant relationship between enzymes of different cellular localization has not been established.