Passage of Fucose-3h Label from the Golgi Apparatus into Dense and Multivesicular Bodies in the Duodenal Columnar Cells and Hepatocytes of the Rat

Fucose 3H is a stable sugar selectively taken up into glycoproteins (1, 2) . Since fucose residues are located at the end of carbohydrate side chains (3), the uptake of fucose indicates completion of the synthesis of these side chains and presumably of the glycoprotein molecules themselves . When duodenal columnar cells were examined after fucose1H injection into rats, the label was observed only in the Golgi apparatus at 2 min, but by 20 min after injection was also found at all cell surfaces (4) . Presumably a glycoprotein completed in the Golgi apparatus was rapidly transferred to the outer surface of the plasma membrane to be added to the "cell coat ." In the rest of the cell, some radioactivity was associated with vesicles, which may be the carriers of glycoprotein from Golgi apparatus to cell coat (4, 5) . It was also noted recently that some radioactivity was located in dense and multivesicular bodies (6, 7) . A similar finding has been reported in lymphocytes (8) . The present investigation is a systematic examination of this phenomenon in duodenal columnar cells and hepatocytes.