Axonal transport was studied in galactose-fed rats. Precursors for proteins and glycoproteins were injected into the fifth lumbar spinal ganglion and retrograde axonal transport as well as slow axonal transport were estimated at different time intervals during the following 4 weeks. Galactose-feeding was found to produce a progressive reduction of the retrograde axonal transport of glycoproteins in intact nerve (2.9 +/- 0.2 (arbitrary units) after five days of galactose-feeding as compared to 1.9 +/- 0.7 after 28 days, 2p = 0.025). The slow axonal transport velocity of structural proteins was reduced from 0.97 +/- 0.09 mm/day to 0.84 +/- 0.04 mm/day, 2p = 0.0030. The present findings as well as structural and electrophysiological abnormalities of the nerves of galactose-fed rats are similar to the changes found in diabetic rats. The similarities point to a decisive role for glucose or its metabolites in the development of diabetic neuropathy.