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Alanine Aminotransferase Apoenzyme in Dogs
Article first published online: 23 FEB 2009
© 1998 American Society for Veterinary Pathology
Veterinary Clinical Pathology
Volume 27, Issue 1, pages 26–30, March 1998
How to Cite
Mesher, C. I., Rej, R. and Stokol, T. (1998), Alanine Aminotransferase Apoenzyme in Dogs. Veterinary Clinical Pathology, 27: 26–30. doi: 10.1111/j.1939-165X.1998.tb01076.x
- Issue published online: 23 FEB 2009
- Article first published online: 23 FEB 2009
- alanine aminotransferase;
- serum chemistry analyzer
Abstract— Unusually low serum activity of alanine aminotransferase (ALT) was detected in a Rottweiler dog with gastric dilatation-volvulus. Activity of ALT in the same sample was found to be much higher (estimated increase of 14, 225%) when measured by methods adding the cofactor pyridoxal-5′-phosphate (P5P), indicating that nearly all serum ALT was in the apoenzyme form. An investigation was undertaken to determine the frequency of high serum aminotransferase apoenzyme levels in dogs. Eighty canine serum samples submitted to the Clinical Pathology Laboratory at Cornell University were assayed for ALT and aspartate aminotransferase (AST) in the presence or absence of exogenous P5P. In 79 dogs, inclusion of P5P in the ALT assay resulted in a median increase in ALT activity of 9.6% (range -7.1% to 46.5%). Inclusion of P5P in the AST assay resulted in a median decrease in AST activity of-6.3% (range -33.3% to 25.0%) in all 80 dogs. One dog had an increase of 336% in ALT activity after inclusion of P5P in the assay, but lacked a similar increase in AST activity. The reason for the high levels of ALT apoenzyme in the 2 dogs was not determined.