Evaluation of Serum SDH, GLDH, ICDH and γ-GT Activities in Horses Following CCI₄ Administration

Abstract

To contribute to the enzymological diagnosis of equine hepatic disorder, the levels of serum sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GLDH), and isocitrate dehydrogenase (ICDH) were determined in 50 healthy racehorses in Japan. When expressed with mean and standard deviation, they were 1.4±0.56 for SDH, 1.5±1.1 for GLDH, and 11.1±3.2 for ICDH(mU/ml, 25°C). Mainly, lactate dehydrogenase(LDH), glutamate oxalacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), alkaline phosphatase (A1-P), r-glutamyl transpeptidase (γ-GT), and a-hydroxybutyrate dehydrogenase (α-HBD) were measured for three weeks in three cases of equine liver dysfunction, which had been induced by oral administration with 0.4m1/kg of carbon tetrachloride (CC1₄). Among these enzymes, the change of γ-GT activity was discussed especially. A concomitant significant increase was observed in serum SDH and GLDH activity after CC1₄ administration. A maximum peak of SDH activity was observed 24-48 hours later and GLDH activity 3 days later. Serum ICDH activity was not significantly high, as compared with SDH and GLDH. One week later, SDH, GLDH, and ICDH activities returned to their levels determined before CC1₄ administration. On the other hand, γ-GT maintained considerably high activity for three weeks. From the results of this experiment, it was assumed that SDH and GLDH might be available for the diagnosis of acute liver disease in the very early stage, and γ-GT for the diagnosis of chronic liver disease.