Observations on gamma-glutamyl transferase, 5′-nucleotidase and leucine aminopeptidase activities in the plasma of the horse.

This research examined the effect of age or sex on the activities of certain enzymes in horse plasma, and the manner in which these enzymes are released into plasma in horses with specific medical conditions. The study also investigated these enzymes’ sensitivity as indicators of liver damage.

Overview of the Study

• This study involved 18 horses and sought to understand if their age or sex had any influence on the actions of three specific enzymes in their plasma: gamma-glutamyl transferase (gamma-GT), 5′-nucleotidase (5′-NT) and leucine aminopeptidase (LAP).
• The researchers also tested if these three enzymes were stable after being stored for one month at -20 degrees Celsius.
• They investigated whether there was any significant difference between the activities of these enzymes in the serum and plasma of clinically normal horses.

Investigations into how Enzymes are released into the Plasma

• This part of the study involved 114 horses with various medical conditions, including orthopaedic, gastrointestinal, cardiovascular and hepatic conditions.
• The researchers sought to understand the pattern of release of the three enzymes of interest (gamma-GT, 5′-NT and LAP) into the plasma of these horses.
• The study also aimed to establish a definitive diagnosis of hepatic (liver) disease by conducting a histological examination of the liver.

Findings of the Study

• The research found that the enzymes gamma-GT and 5′-NT were leaked into the plasma in cases of hepatic disease. Gamma-GT proved to be a more sensitive indicator of liver damage.
• The study found that there was an increase in the plasma activities of both gamma-GT and 5′-NT in cases of hepatic necrosis (liver cell death) and in biliary obstruction (blockage of the bile ducts).
• The researchers found that LAP was not a sensitive or specific indicator of liver disease in horses.