title: Erythrocyte glutathione and plasma cysteine concentrations in young versus old dogs.
abstract: OBJECTIVE
  To determine whether older, otherwise healthy, client-owned dogs were deficient in glutathione or cysteine, compared with young healthy pet dogs.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  35 healthy dogs between 7 and 14 years old (older dogs) and 26 healthy dogs between 1 and 3 years old (young dogs).
  
  
  METHODS
  In all dogs, erythrocyte reduced glutathione concentration and plasma cysteine concentration were determined by means of high-performance liquid chromatography.
  
  
  RESULTS
  Median erythrocyte reduced glutathione and plasma cysteine concentrations were not significantly different between young (1.7 mM and 8.3 microM, respectively) and older (1.7 mM and 7.6 microM, respectively) dogs. Significant differences were also not identified when values for young dogs were compared with values for only those dogs>or=11 years old. Similarly, no differences were found between males and females overall or between males and females within age groups, although most dogs were neutered.
  
  
  CONCLUSIONS
  Results suggested that otherwise healthy older pet dogs fed a variety of commercial diets do not have deficiencies in glutathione or cysteine, compared with younger dogs. Findings do not support the routine empirical use of antioxidant supplements, such as precursors of glutathione, to treat presumed circulating antioxidant deficiencies in older healthy dogs.
authors.affiliation: Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706-1102, USA.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Moyer
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Trepanier
mesh_terms: D000367:Age Factors; D000375:Aging / Q000097:blood*; D000821:Animal Feed; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D003430:Cross-Sectional Studies; D003545:Cysteine / Q000097:blood*; D004285:Dogs / Q000097:blood*; D004912:Erythrocytes / Q000737:chemistry*; D005260:Female; D005978:Glutathione / Q000032:analysis*; D008297:Male; D009752:Nutritional Status; D012737:Sex Factors
chemical_list: D005978:Glutathione; D003545:Cysteine