Transport of radioactivity derived from labeled N‐acetylglucosamine in mammalian motor axons

The distribution of radioactivity in L 7 ventral roots after microinjection of N‐acetyl‐ 3 H‐glucosamine into the L 7 segment of the feline neuraxis was examined under several conditions; i.e., the isotope was injected before and after ligation of the roots and various periods were allowed for uptake. The results indicated a transport of radiolabeled macromolecular material in both slow and fast components of axoplasmic flow. Further characterization of the nature of the transported, macromolecular material revealed that more than half of the radioactivity was non‐ultrafilterable even after pronase digestion, only 2% of this activity was incorporated into acidic glycosaminoglycans and the remaining activity was probably derived from glycoproteins.