Glycoconjugate Journal

, Volume 24, Issue 9, pp 531–541

Liver-specific increase of UTP and UDP-sugar concentrations in rats induced by dietary vitamin B6-deficiency and its relation to complex N-glycan structures of liver membrane-proteins

  • Agnes B. Renner
  • Kathrin Rieger
  • Detlef Grunow
  • Martin Zimmermann-Kordmann
  • Martin Gohlke
  • Werner Reutter
Article

DOI: 10.1007/s10719-007-9048-x

Cite this article as:
Renner, A.B., Rieger, K., Grunow, D. et al. Glycoconj J (2007) 24: 531. doi:10.1007/s10719-007-9048-x

Abstract

This is the first known report on the influence of vitamin B6-deficiency on the concentration of UDP-sugars and other uracil nucleotides in rats. Animals aged 3 weeks or 2 months were fed a vitamin B6-free diet for periods varying from 3 days to 7 weeks. Nucleotides were quantified by enzymatic-photometry and by SAX-high precision liquid chromatography. In 3 week-old rats, vitamin B6-deficiency resulted in an up to 6.3-fold increase in the concentrations of UTP, UDP, UMP and UDP-sugars and less of CTP in rat liver, while no changes were observed in older rats. In young rats, the concentration of uracil nucleotides started to increase after 1 week diet, with a maximum after 2 weeks. After 5 weeks, the concentrations returned to normal values. In heart, lungs, kidney and brain, concentrations were measured after 2 weeks diet in young rats. In contrast to liver, the heart muscle uracil nucleotide concentrations were decreased by 40%. In kidney, the sum of UTP, UDP and UMP showed a decrease of 40%, whereas UDP-sugars were increased 1.4-fold. In the lungs, nucleotide concentrations were mostly unaffected by vitamin B6-deficiency, despite a 70% increase of UDP-GA. In brain, UDP-Glc, UDP-Gal and the sum of CTP and CDP showed an increase of 30–50%. We became surprised that the increased UDP-sugar concentrations did not influence the structure of liver plasma membrane-N-glycans. Despite the 4 to 6-fold increase of UTP and UDP-sugars, no changes in the complexity or sialylation of these N-glycans could be detected. This study demonstrates that, especially in liver, pyridoxal phosphate is closely involved in the control of uracil nucleotides during a defined period of development. In contrast to in vitro experiments, in vivo N-glycan biosynthesis in liver is regulated by a more complex or higher mechanism than substrate concentrations.

Keywords

Vitamin B6-deficiencyUTPUDP-sugarsN-glycosylation of plasma membrane glycansRat liver

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Agnes B. Renner
    • 1
    • 2
  • Kathrin Rieger
    • 1
    • 3
  • Detlef Grunow
    • 1
  • Martin Zimmermann-Kordmann
    • 1
  • Martin Gohlke
    • 1
  • Werner Reutter
    • 1
  1. 1.Institut für Biochemie und MolekularbiologieCharité - Universitätsmedizin BerlinBerlinGermany
  2. 2.AugenklinikCharité - Universitätsmedizin BerlinBerlinGermany
  3. 3.Medizinische Klinik III, HämatologieOnkologie und Transfusionsmedizin,Charité - Universitätsmedizin BerlinBerlinGermany