title: Metabolic fate of intravenously administered N-acetylneuraminic acid-6-14C in newborn piglets.
abstract: BACKGROUND
  Sialic acid (N-acetylneuraminic acid), a component of gangliosides and sialylglycoproteins, may be a conditional nutrient in early life because endogenous synthesis is limited. The aim of this study was to investigate the metabolic fate of intravenously administrated N-acetylneuraminic acid-6-14C (sialic acid) in piglets.
  
  
  METHODS
  Three-day-old male domestic piglets (Sus scrofa) were injected via the jugular vein with 5 microCi (11-12 x 10(6) cpm) of N-acetylneuraminic acid-6-14C (specific activity of 55 mCi/mmol). Blood samples were collected at regular intervals over the next 120 min. The organs were then removed and the urine collected for determination of residual radioactivity.
  
  
  RESULTS
  Within 2 min of injection, 80% of the activity was removed from the blood and by 120 min the remaining activity approached 8%. At 120 min, the brain contained significantly more radioactivity (cpm/g tissue) than the liver, pancreas, heart and spleen, but less than the kidneys. Within the brain, the percentage of total injected activity was highest in the cerebrum (0.175 +/-0.008) followed by the cerebellum (0.0295 +/-0.006, p=0.00006) and the thalamus (0.029 +/- 0.006, p =0.00003).
  
  
  CONCLUSIONS
  An exogenous source of sialic acid is capable of crossing the blood-brain barrier and being taken up into various tissues. The findings suggest that dietary sources of sialic acid may contribute to early brain development in newborn mammals.
authors.affiliation: Human Nutrition Unit, School of Molecular and Microbial Biosciences, G08 University of Sydney, NSW 2006, Australia. B.Wang@mmb.usyd.edu.au
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Jeff A
authors.initials: JA
authors.lastname: Downing
authors.forename: Peter
authors.initials: P
authors.lastname: Petocz
authors.forename: Jennie
authors.initials: J
authors.lastname: Brand-Miller
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Bryden
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002250:Carbon Radioisotopes; D007262:Infusions, Intravenous; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D019158:N-Acetylneuraminic Acid / Q000493:pharmacokinetics*; D009928:Organ Specificity; D013154:Spleen / Q000378:metabolism; D034421:Sus scrofa / Q000097:blood / Q000378:metabolism* / Q000652:urine; D014018:Tissue Distribution
chemical_list: D002250:Carbon Radioisotopes; D019158:N-Acetylneuraminic Acid