L-fucose labeling of brain tumors in rats.

These studies used L-[14C]fucose to identify 9L brain tumors in rats. Ten days after intracranial implantation of 9L tumor cells, labeled L-fucose was injected intravenously. Autoradiography demonstrated high levels of radioactive L-fucose in the resultant 9L tumors but very little L-fucose in normal brain tissue. In vitro studies comparing uptake of labeled fucose into 9L cells, normal rat fibroblasts and transformed rat fibroblasts, rat astrocytes, and human brain tissue suggest that fucose is not preferentially transported into the 9L cells. These data imply that a permissive blood-brain barrier rather than differences in fucose metabolism underlie 9L tumor labeling.