Axonal transport of choline acetyltransferase and 6-phosphofructokinase activities in genetically diabetic mice

This study examined the anterograde axonal transport of activities of the cytoplasmic enzymes choline acetyltransferase and 6-phosphofructokinase in genetically diabetic C57BL/Ks (db/db) mice and their nondiabetic (+/?) littermates. Diabetic mice exhibited marked reductions in the accumulation of both choline acetyltransferase and 6-phosphofructokinase activity against a constriction of the left sciatic nerve (38% and 51% of nondiabetic values, respectively). Enzyme activities per unit length of unconstricted nerve were not different from those of nondiabetic mice. The nerves of diabetic mice did not accumulate measurable amounts of sorbitol or fructose and showed no myo-inositol depletion. Thus this study concludes that, in diabetic mice, the deficits in anterograde axonal transport of these two enzymes do not arise from the accumulation of sorbitol and fructose nor from depletion of nerve free myo-inositol.