title: Short-term exogenous galactose supplementation does not influence rate of appearance of galactose in patients with classical galactosemia.
abstract: BACKGROUND
  Recently, evidence has been presented that adult patients with classical galactosemia have higher than expected galactose tolerance. This may be caused by a decrease of endogenous galactose production with ageing. Alternatively, suppression of endogenous galactose production by exogenous galactose might be implicated. The aim of this study was to determine if the rate of appearance of galactose is suppressed by exogenous galactose.
  
  
  METHODS
  Two adult patients with classical galactosemia and three healthy control subjects were given a primed continuous infusion of D-[1-13C]galactose to determine the rate of appearance of galactose (GAR, expressed as micromol/kg/h) before and during additional galactose supplementation. After initial assessment of GAR (GAR1), GAR was determined during doubled (GAR2) or quadrupled (GAR4) galactose infusion.
  
  
  RESULTS
  GAR1 was 2.48 and 2.44 in patients 1 and 2, and 0.46, 0.34, and 0.39 in control subjects 1, 2, and 3, respectively. GAR(2) was 2.43 and 2.13 in patients 1 and 2, and 0.57, 0.38, and 0.47 in control subjects 1, 2, and 3, respectively. In patient 1 the experiment was repeated during quadrupled galactose infusion. Here GAR1 was 3.01 and GAR4 was 3.26.
  
  
  CONCLUSIONS
  No significant differences between GAR before and during additional galactose infusion were found in patients and in control subjects. GAR1 was significantly higher in patients than in control subjects. We conclude that the rate of appearance of galactose is not influenced by exogenous galactose, at least under short-term conditions, in patients with classical galactosemia and in control subjects.
authors.affiliation: Department of Paediatrics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Hidde H
authors.initials: HH
authors.lastname: Huidekoper
authors.forename: Annet M
authors.initials: AM
authors.lastname: Bosch
authors.forename: Saskia N
authors.initials: SN
authors.lastname: van der Crabben
authors.forename: Hans P
authors.initials: HP
authors.lastname: Sauerwein
authors.forename: Mariëtte T
authors.initials: MT
authors.lastname: Ackermans
authors.forename: Frits A
authors.initials: FA
authors.lastname: Wijburg
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002940:Circadian Rhythm; D005690:Galactose / Q000008:administration & dosage* / Q000378:metabolism; D005693:Galactosemias / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans
chemical_list: D005690:Galactose