ENZYMES CONCERNED WITH DIGESTION OF LIPIDS 55 



and rabbit brain. 206,316 ' -318 Some portions of the brain were found to have 

 twenty times the concentration of cholinesterase found in other areas of the 

 organ. The highest levels have been reported in the central grey matter 

 (i.e. putamen) and the lowest values in the cortex and white matter. The 

 concentration of cholinesterase parallels that of monoamine oxidase, the 

 function of which is to destroy epinephrine and other monoamines. 318,319 

 Burgen and Chipman 313 noted that the highest cholinesterase content was 

 to be found in the cerebellar hemispheres, and the lowest amount in the 

 anterior spinal roots. 



Both true and pseudocholinesterases have been reported in peripheral 

 nerves, by Sawyer and Hollinshead 320 and by Sawyer 321 alone. According 

 to Nachmansohn, 174 cholinesterase is concentrated at the neuron surface. 

 A very high level occurs in the motor end-plates of the neuromuscular junc- 

 tions, and in the synapses. When the sciatic nerves of the guinea pig were 

 sectioned, Sawyer 321 found no change in the pseudocholinesterase during 

 Wallerian degeneration, but there was a 60% loss of the true enzyme. On 

 regeneration of the nerve, a considerable increase in true cholinesterase 

 obtained. It was concluded that as much as two-thirds of the true cholin- 

 esterase is secreted by the axis cylinders, while the rest of the e-cholin- 

 esterase is produced by some other element, possibly by the sheath cells. 

 In contradistinction to this finding, the pseudo-enzyme is probably resident 

 in the connective tissue. Kalsbeek and co-workers 322 report that human 

 cerebrospinal fluid contains both pseudo- and true cholinesterase, but no 

 ali-esterase. Thus, not only acetylcholine and acetyl-/3-methylcholine 

 were hydrolyzed by cerebrospinal fluid, but also butyrylcholine and some- 

 times tributyrin. 



c'. Cholinesterases in Glandular Tissues: Cholinesterase of the non- 

 specific type (s) has been reported in mouse and rat livers, where the activ- 

 ity is influenced by sex hormones. 276 ~ 278 Zachs and Welsh 323 have recently 

 demonstrated the presence of pseudocholinesterase in the mitochondria 

 and microsomes of rat liver. Specific cholinesterase was also found in 

 rat liver, but it was of a lower order than the pseudo type. It is suggested 



316 D. Nachmansohn, Bull. soc. chim. bid., 21, 761-796 (1939). 



317 G. Pighini, Riv. sper. frenatria med. legale delle alienazioni mentali, 62, 439-465 

 (1938). 



318 H. Birkhauser, Helv. Chim. Acta, 23, 1071-1086 (1940). 



319 H. Langemann, Helv. Physiol. Pharmacol. Acta, 2, 367-375 (1944). 



320 C. H. Sawyer and W. H. Hollinshead, J. Neurophysiol., 8, 137-153 (1945). 



321 C. H. Sawyer, Am. J. Physiol., 146, 246-253 (1946). 



322 F. Kalsbeek, J. A. Cohen, and B. R. Bovens, Biochim. et Biophys. Acta, 5, 548-560 

 (1950). 



323 S. I. Zachs and J. H. Welsh, Am. J. Physiol., 165, 620-623 (1951). 



