title: Effect of serum storage, anti-inflammatory oral doses of prednisone, and spontaneous hyperadrenocorticism on serum glutamate dehydrogenase activity in dogs.
abstract: BACKGROUND
  Glutamate dehydrogenase (GLDH) is a mitochondrial enzyme with highest activity in periacinar hepatocytes. It is reported to be a sensitive indicator of hepatic injury; however, results of studies regarding tissue specificity are contradictory.
  
  
  OBJECTIVE
  The purpose of the study reported here was to examine the effect of 3 factors on serum GLDH activity in dogs: serum storage, anti-inflammatory oral doses of prednisone, and spontaneous hyperadrenocorticism (HAC).
  
  
  METHODS
  Stability of enzyme activity was determined by comparing serum samples stored at approximately 20 degrees C, 4 degrees C, and 20 degrees C for 4, 24, 48, and 72 hours, 1 week, and 6 months. To determine whether orally administered prednisone affected GLDH activity, the median difference in serum GLDH activity was compared between 5 untreated control dogs and 8 dogs that had received a tapering oral dose of prednisone. Lastly, GLDH enzyme activity was compared between 17 dogs with HAC and 16 age-matched controls.
  
  
  RESULTS
  GLDH activity remained stable for 48 hours, 1 week, and 6 months, in serum stored at approximately 20 degrees C, 4 degrees C, and 20 degrees C, respectively. The median change in GLDH activity was not significantly different between dogs receiving prednisone and controls; however, dogs with HAC had significantly higher values than those of age-matched controls.
  
  
  CONCLUSIONS
  Serum samples should be maintained at 4 degrees C if analysis of GLDH activity will be delayed by >48 hours; serum stored at 20 degrees C yields reliable results for up to 6 months. Serum GLDH activity was not increased in most dogs receiving short-term, anti-inflammatory oral doses of prednisone, in contrast to its increased activity in dogs with HAC.
authors.affiliation: Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Canada.
authors.forename: Heidi G
authors.initials: HG
authors.lastname: Peta
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Carr
authors.forename: Sherry L
authors.initials: SL
authors.lastname: Myers
authors.forename: Danny J
authors.initials: DJ
authors.lastname: Joffe
authors.forename: Beverly A
authors.initials: BA
authors.lastname: Kidney
mesh_terms: D000284:Administration, Oral; D000308:Adrenocortical Hyperfunction / Q000201:enzymology / Q000662:veterinary*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000009:adverse effects / Q000627:therapeutic use; D003872:Dermatitis / Q000188:drug therapy; D004283:Dog Diseases / Q000097:blood* / Q000201:enzymology*; D004285:Dogs; D005969:Glutamate Dehydrogenase / Q000097:blood*; D011241:Prednisone / Q000008:administration & dosage* / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000893:Anti-Inflammatory Agents; D005969:Glutamate Dehydrogenase; D011241:Prednisone