Expression of the hexose transporters GLUT1 and GLUT2 during the early development of the human brain

We used immunohistochemistry with anti-glucose transporter antibodies to do cument the presence of facilitative hexose transporters in the fetal human brain. GLUT1 is expressed in all regions of the fetal brain from ages 10 to 21 weeks. GLUT1 was present in the endothelial cells of the brain capillar ies, the epithelial cells of the choroid plexus and neurons. High expressio n of GLUT2 was observed in the granular layer of the cerebellum in brains 2 1 weeks old, but GLUT2 immunoreactivity was absent at earlier stages. GLUT3 and GLUT4 immunoreactivities were absent at all stages studied. GLUT5 immu noreactivity was evident only in the cerebellar region of 21-week old fetal brains. We conclude that GLUT1 plays a fundamental role in early human bra in development. The data also suggest that the cerebellum of the developing brain has the capacity to transport fructose, a substrate that has not bee n previously identified as a source of metabolic energy in the adult human brain. (C) 1999 Published by Elsevier Science B.V. All rights reserved.