Regional distribution of adenosine deaminase in the human neuraxis.

Adenosine deaminase was determined in 28 different areas of the human neuraxis in 5 adult male cadavers, with no known disease of the nervous system, using a very sensitive colorimetric method. The enzyme was highest in the frontal lobe white matter, and lowest in the medulla and all levels of the spinal cord. Enzyme content was about twice as great in the white matter of the frontal and temporal lobes and cerebellum as it was in the cortical gray matter of these areas, but only slightly higher in the white matter of the parietal and occipital lobes as compared to gray. Average values of the enzyme were found in the remaining areas of the brain, with the exception of the pons and cerebellar white matter, where a higher than average value was noted.