title: Variations in metabolic response to TPN are influenced more by sex than by light exposure.
abstract: BACKGROUND
  Failure to protect total parenteral nutrition (TPN) solutions from ambient light induces the generation of peroxides, which contributes to the oxidation of several amino acids. We hypothesized that photo-protection improves the metabolic response to TPN.
  
  
  OBJECTIVE
  To study the effects of photo-protecting TPN on urinary nitrogen and vitamin C excretion and to evaluate in premature infants the influence of sex.
  
  
  METHODS
  Premature infants were randomized to receive from birth light-exposed (LE) or light-protected (LP) TPN. Upon reaching full TPN, parenteral nutrient intakes were correlated with normalized urinary nitrogen and vitamin C concentrations.
  
  
  RESULTS
  No differences were observed between LE and LP. However, sex-related differences were observed in nitrogen and vitamin C handling. In boys, 50% of the nitrogen loss was explained by parenteral amino acid intake, whereas in girls, no correlation was found. The inverse correlation observed between intake and urinary excretion only in girls suggests a state of greater vitamin C utilization in girls.
  
  
  CONCLUSIONS
  These results demonstrate that sex-related differences in nitrogen/protein metabolism reported during enteral nutrition are seen during TPN as well. Sex is an important variable that will need to be taken into account in future studies evaluating the potential clinical effects of photo-protecting TPN.
authors.affiliation: Division of Neonatology, Children's and Women's Hospitals, University of British Columbia, Vancouver, Canada.
authors.forename: Adele
authors.initials: A
authors.lastname: Harrison
authors.forename: Minesh
authors.initials: M
authors.lastname: Khashu
authors.forename: James
authors.initials: J
authors.lastname: Friel
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Lavoie
authors.forename: Philippe
authors.initials: P
authors.lastname: Chessex
mesh_terms: D001205:Ascorbic Acid / Q000008:administration & dosage / Q000378:metabolism* / Q000652:urine; D003404:Creatinine / Q000652:urine; D004355:Drug Stability; D004356:Drug Storage; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008027:Light / Q000009:adverse effects*; D015227:Lipid Peroxidation; D008297:Male; D009584:Nitrogen / Q000008:administration & dosage / Q000378:metabolism* / Q000652:urine; D010289:Parenteral Nutrition, Total; D010777:Photochemistry; D012737:Sex Factors; D014815:Vitamins / Q000008:administration & dosage / Q000378:metabolism* / Q000652:urine
chemical_list: D014815:Vitamins; D003404:Creatinine; D009584:Nitrogen; D001205:Ascorbic Acid