56 II. DIGESTION AND ABSORPTION OF FATS 



that the attraction of the enzyme receptor groups for the alkylated quater- 

 nary nitrogen groups of Janus Green B and similar basic dyes may be re- 

 sponsible for the staining of the mitochondria of liver and motor end- 

 plates by these dyes. 



According to Langemann, 324 and Vincent and Lagreu, 325 the s-type of 

 cholinesterase is present in dog pancreas. As would be expected from its 

 presence in the pancreatic gland, pseudocholinesterase likewise occurs in 

 pancreatic juice, in which it may be present in a high concentration. 326 

 The amounts of cholinesterase secreted appear to vary according to the 

 stimulus employed to elicit its flow. 326 The salivary glands, which have a 

 close histological relationship to pancreatic tissue, are another source of 

 cholinesterase. While the s-type of cholinesterase has been reported in the 

 parotid glands of the pig and guinea pig, the e-type has been found in these 

 glands of the cow and rabbit, and a mixture of the two types has been 

 recorded for the parotid glands of the cat and dog. 307,327 McCance and 

 Brown 326 have confirmed the high rate of hydrolysis of acetylcholine by 

 parotid saliva. Cholinesterase of the s-type has been recorded in the 

 human ovary, 324 while Sekine 328 reported the presence of the specific type 

 of this enzyme in the seminal plasma, where it is about one-third as active 

 as in human serum. This worker also reports that the motion of pig 

 spermatozoa is activated by cholinesterase and depressed by eserine. Some 

 confusion would seem to exist as regards the type of the cholinesterase, as it 

 does not split benzoylcholine but does hydrolyze butyrylcholine at a higher 

 rate than is the case with the brain enzyme. Placenta, 329 like the red blood 

 cells, provides a second example of nerve-free tissue which contains almost 

 exclusively the true cholinesterase usually associated with nervous activity. 



d'. Cholinesterases in Miscellaneous Tissues: In an extensive study of 

 the type and distribution of cholinesterases in rat tissues, Ord and Thomp- 

 son 330 demonstrated the presence of the s- and e-types in stomach, liver, 

 lung, and submaxillary gland; in the case of heart auricle and ventricle, 

 intestinal muscle and mucosa, Harderian gland, and skin, cholinesterase-s 

 predominated. Brooks and Myers 331 found that no increase in true cholin- 

 esterase occurred in the muscle tissue of guinea pigs whose body weight had 



324 H. Langemann, Helv. Physiol. Pharmacol. Acta, 2, C17-C18 (1944). 



325 D. Vincent and R. Lagreu, Bull. soc. chim. biol, 31, 1043-1045 (1949). 



326 R. A. McCance and L. M. Brown, Nature, 168, 788-789 (1951). 



327 C. H. Sawyer, Science, 101, 385-386 (1945). 



328 T. Sekine, J. Biochem. (Japan), 38, 171-179 (1951). 



329 M. G. Ord and R. H. S. Thompson, Nature, 165, 927-928 (1950). 



330 M. G. Ord and R. H. S. Thompson, Biochem. J., 46, 346-352 (1950). 



331 V. B. Brooks and D. K. Myers, J. Physiol., 116, 158-167 (1952). 



