I am interested in determining the amount of glucose that is taken up by a couple of cancer cell lines. I have tried a couple of commercial kits to no avail, so am attempting to use NBDG and measure it by fluorescence as has been done in the past. I have read that both 6-NBDG and 2-NBDG can be used for this purpose. My understanding of why 2-NBDG would be good is so that the the 6 position can then be phosphorylated (by hexokinase), not metabolized any further in glycolysis thus is retained in the cell (the theory behind 18F-FDG PET imaging), but I have also read that it does in fact get metabolized further - although I cannot find anything specific in the literature discussing this. On the other hand 6-NBDG is taken up by the cell but cannot be phosphorylated by hexokinase as it already modified at the 6-position. Would this mean that the 6-NBDG can then be transported back out of the cell and thus cannot be used to determine the amount of its accumulation inside the cell? Thank you for your input.