title: Urinary pyridinoline and deoxypyridinoline excretion in children.
abstract: OBJECTIVE
  There are few data on urinary markers of collagen breakdown in children. We have determined a normal range for urinary pyridinoline and deoxypyridinoline in children, assessed the variability in excretion in individual children and examined the effect of GH treatment on the excretion of these collagen cross-links.
  
  
  METHODS
  A cross-sectional study of a group of healthy children and sequential samples from children receiving GH treatment.
  
  
  METHODS
  One hundred and nine healthy children aged 2-15 years, 8 healthy children aged 4-11 years and 4 children receiving GH treatment.
  
  
  METHODS
  Total pyridinoline and deoxypyridinoline excretion were measured by high performance liquid chromatography after initial acid hydrolysis and cellulose extraction steps. Serum parathyroid hormone was measured using a two-site immunoradiometric assay and urinary hydroxyproline by Ehrlich's reaction using a colorimetric assay. Pyridinoline and deoxypyridinoline excretion were expressed as a ratio against urine creatinine.
  
  
  RESULTS
  High excretion of pyridinoline (Pyr) and deoxypyridinoline (DPyr) was seen at all ages with no apparent relation to age (mean Pyr/Cr 115 nmol/mmol and DPyr/Cr 31 nmol/mmol). No correlation was found with serum parathyroid hormone or urinary hydroxyproline excretion. Marked day to day variation was seen in individual children. A progressive rise in excretion was seen in children receiving GH treatment with no significant correlation to height velocity.
  
  
  CONCLUSIONS
  There is a high excretion of the pyridinium cross-linking amino acids in children of all ages compared to adults. However, a high variability exists in single morning urine samples which will limit the usefulness of these markers in growing children.
authors.affiliation: Institute of Child Health, Royal Liverpool Children's Hospital, Alder Hey, UK.
authors.forename: N J
authors.initials: NJ
authors.lastname: Shaw
authors.forename: J
authors.initials: J
authors.lastname: Dutton
authors.forename: W D
authors.initials: WD
authors.lastname: Fraser
authors.forename: C S
authors.initials: CS
authors.lastname: Smith
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000596:Amino Acids / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D013006:Growth Hormone / Q000627:therapeutic use; D006801:Humans; D008297:Male; D012016:Reference Values
chemical_list: D000596:Amino Acids; C015484:pyridinoline; D013006:Growth Hormone; C036020:deoxypyridinoline; D003404:Creatinine