Four enzymes, representative for different steps of carbohydrate metabolism, were studied in L3–L4 segments of rat spinal cord. The ventral horns were dissected from frozen dried sections and the enzyme activities were measured microfluorometrically by their quantitative reduction of NADP. In control rats the enzyme activities remained constant during the growth of the animals from 4 to 16 weeks of age. In rats which had neurological symptoms and axonal lesions after feeding of β,β-iminodipropionitrile, the activity of glucose-6-phosphate dehydrogenase was constantly increased during the same age period, while other enzymes were not. These findings are considered in relation to the findings of other investigators that drugs, dehydration, nerve transection, and other procedures affect the same enzymes.
