ASTROCYTE-CONDITIONED MEDIUM INDUCES BLOOD-BRAIN-BARRIER PROPERTIES IN ENDOTHELIAL-CELLS

1. We evaluated the induction of endothelial barrier functions by the type 1 astrocyte-derived supernatant in culture using horseradish pero xidase (HRP) as a parameter, 2, A gel filtration fraction (molecular w eight 16-20 kDa) of type 1 astrocyte-derived supernatant reduced plasm alemmal vesicles and induced tight junctions in endothelial cells, 3, In addition, this fraction promoted the uptake of [H-3]-glucosamine by endothelial cells, This cell activity disappeared after heating at 95 degrees C for 10 min and was sensitive to trypsin, 4, These results s uggest that a type 1 astrocyte-derived protein factor(s) promotes prot eoglycan synthesis with a resultant increase in charge selectivity in endothelial cells and plays an important role in the induction of bloo d-brain barrier functions.