Blood-Brain Transfer of Galactose in Experimental Galactosemia, with Special Reference to the Competitive Interaction Between Galactose and Glucose
Article first published online: 5 OCT 2006
Journal of Neurochemistry
Volume 43, Issue 6, pages 1654–1662, December 1984
How to Cite
Gjedde, A. (1984), Blood-Brain Transfer of Galactose in Experimental Galactosemia, with Special Reference to the Competitive Interaction Between Galactose and Glucose. Journal of Neurochemistry, 43: 1654–1662. doi: 10.1111/j.1471-4159.1984.tb06092.x
- Issue published online: 5 OCT 2006
- Article first published online: 5 OCT 2006
- Received March 8, 1984; accepted May 14, 1984.
- Blood-brain barrier;
- Competitive inhibition;
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.