Blood‐Brain Transfer of Galactose in Experimental Galactosemia, with Special Reference to the Competitive Interaction Between Galactose and Glucose

Albert Gjedde

Research output: Contribution to journalArticlepeer-review

Abstract

The interaction between glucose and galactose during transport across the cerebral capillary endothehum was studied in anesthetized rats. Although galactose is present in the diet of suckling mammals and is a potential substrate for brain metabolism in adult mammals, its effect on glucose transport in adult rats is unknown. A kinetic model was formulated to analyze the effect of chronically elevated galactose levels on glucose transport in adult rats. The analysis indicated that galactose and glucose compete for the same transport mechanism in the cerebral capillary endothelium. The Tmax of glucose and galactose were both about 380 μmol 100 g‐1 min‐1 and the Kt of galactose (30 mM) was about three times that of glucose (10 mM). During prolonged galactosemia in adult rats, neither the Tmax, nor the Kt of either competitor changed substantially when compared with rats subjected to acute galactosemia. At 10 mM galactose in plasma in rats with acute galactosemia, the inhibition of glucose transport, simulated a 25% reduction of plasma glucose, and in rats with chronic galactosemia a 20% reduction. This moderate effect is in contrast to the effect of galactose in suckling rats in which 10 mM galactose in plasma reduced the glucose transport to a level corresponding to a 50% reduction of the plasma glucose concentration.

Original languageEnglish (US)
Pages (from-to)1654-1662
Number of pages9
JournalJournal of Neurochemistry
Volume43
Issue number6
DOIs
StatePublished - Dec 1984

Keywords

  • Blood‐brain barrier
  • Competitive inhibition
  • Galactose
  • Galactosemia
  • Glucose

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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