title: Circadian and postprandial variation in plasma citrulline concentration in healthy dogs.
abstract: OBJECTIVE
  To evaluate circadian and postprandial variations in plasma citrulline concentration in healthy dogs.
  
  
  METHODS
  8 healthy Beagles.
  
  
  METHODS
  Blood samples were collected from dogs after 12 hours of food withholding (0 hours; 8:00 am) and then every 2 hours for 12 hours (until 8:00 pm) and again at 24 hours (8:00 am the next day). The same protocol was repeated, with the only difference being that a meal was given immediately after the 0-hour sample collection point. Plasma citrulline concentration was measured by ion exchange chromatography.
  
  
  RESULTS
  No significant difference in plasma citrulline concentration was identified among measurement points when food was withheld. Mean ± SD plasma citrulline concentration at 4 hours (72.2 ± 12.7 μmol/L) and 24 hours (56.1 ± 12.5 μmol/L) after dogs were fed was significantly different from that at 0 hours (64.4 ± 12.7 μmol/L).
  
  
  CONCLUSIONS
  Plasma citrulline concentration had no circadian variation in unfed dogs but increased significantly in fed dogs 4 hours after a meal. Therefore, food should be withheld from dogs for 8 to 12 hours before blood sample collection for measurement of citrulline concentration.
authors.forename: Julien M
authors.initials: JM
authors.lastname: Dahan
authors.forename: Celine
authors.initials: C
authors.lastname: Giron
authors.forename: Didier
authors.initials: D
authors.lastname: Concordet
authors.forename: Olivier
authors.initials: O
authors.lastname: Dossin
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D002956:Citrulline / Q000493:pharmacokinetics*; D004285:Dogs / Q000097:blood / Q000378:metabolism*; D005260:Female; D008297:Male; D019518:Postprandial Period
chemical_list: D002956:Citrulline