title: Effects of chronic renal disease on the transport of vitamin A in plasma and urine of dogs.
abstract: OBJECTIVE
  To determine plasma and urine concentrations of retinol, retinyl esters, retinol-binding protein (RBP), and Tamm-Horsfall protein (THP) in dogs with chronic renal disease (CRD).
  
  
  METHODS
  17 dogs with naturally developing CRD and 21 healthy control dogs.
  
  
  METHODS
  A diagnosis of CRD was established on the basis of clinical signs, plasma concentrations of creatinine and urea, and results of urinalysis. Concentrations of retinol and retinyl esters were measured by use of reverse-phase high-performance liquid chromatography. Concentrations of RBP and THP were measured by use of sensitive ELISA systems.
  
  
  RESULTS
  Dogs with CRD had higher plasma concentrations of retinol, which were not paralleled by differences in plasma concentrations of RBP. Calculated ratio of urinary total vitamin A (sum of concentrations of retinol and retinyl esters to creatinine concentration) and ratio of the concentration of urinary retinyl esters to creatinine concentration did not differ between groups. However, we detected a significantly higher retinol-to-creatinine ratio in the urine of dogs with CRD, which was paralleled by a higher urinary RBP-to-creatinine ratio. Thus, in dogs with CRD, the estimated fractional clearance of total vitamin A, retinol, and RBP was increased. Furthermore, dogs with CRD had a reduced urinary THP-to-creatinine ratio.
  
  
  CONCLUSIONS
  Results of this study documented that CRD affects the concentrations of retinol in plasma and urine of dogs. Analysis of the data indicates that measurement of urinary RBP and urinary THP concentrations provides valuable information that can be helpful in follow-up monitoring of dogs with CRD.
authors.affiliation: Institute of Nutritional Science, University of Potsdam, Potsdam-Rehbrücke, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Raila
authors.forename: Simone
authors.initials: S
authors.lastname: Forterre
authors.forename: Barbara
authors.initials: B
authors.lastname: Kohn
authors.forename: Leo
authors.initials: L
authors.lastname: Brunnberg
authors.forename: Florian J
authors.initials: FJ
authors.lastname: Schweigert
mesh_terms: D000818:Animals; D001692:Biological Transport; D004283:Dog Diseases / Q000097:blood* / Q000652:urine*; D004285:Dogs; D005260:Female; D007676:Kidney Failure, Chronic / Q000097:blood / Q000378:metabolism* / Q000652:urine / Q000662:veterinary*; D008297:Male; D009088:Mucoproteins / Q000097:blood / Q000652:urine; D012177:Retinol-Binding Proteins / Q000032:analysis / Q000652:urine; D054839:Retinol-Binding Proteins, Plasma; D058949:Uromodulin; D014801:Vitamin A / Q000031:analogs & derivatives / Q000097:blood* / Q000378:metabolism / Q000652:urine*
chemical_list: D009088:Mucoproteins; D012177:Retinol-Binding Proteins; D054839:Retinol-Binding Proteins, Plasma; D058949:Uromodulin; D014801:Vitamin A