278 INTERNAL SECRETION 



that the hypotensive action of these extracts is independent of 

 cholin. 



The wide distribution of cholin in the organism was em- 

 phasized by Claude and Blanchetiere (1907), who also pointed 

 out that cholin is present in the greater number of tissues and 

 secretions of the body, though not in a free state but in combina- 

 tion with lecithin, v. Fiirth and Schwarz showed that cholin is 

 present in intestinal extract and in secretin (so-called), and that 

 it stimulates the secretory activity of the pancreas and of the 

 salivary glands. The effect of cholin upon secretion is com- 

 pletely neutralized by atropine. They also found that the con- 

 stituent of the thyroid which lowers blood-pressure, is identical 

 with cholin. Schwarz and Lederer found depressant substances, 

 which they identified with cholin, in extracts of thymus, spleen and 

 lymph glands. 



Finally, Gautrelet found cholin in the pancreas, spleen, ovary, 

 thyroid, kidney, testicle, pituitary and salivary glands, bone 

 marrow, and gastric and intestinal mucous membranes of animals 

 of various species. He came to the conclusion that the common 

 active principle of the extracts of those organs which were included 

 by Livon in the description " hypotensive glands," is cholin, the 

 activity of which is antagonistic to that of adrenalin. He divides 

 the internal secretory organs into those which are cholinogenic 

 and those which are adrenalinogenic (chromaffine), and he believes 

 that the regulation of arterial pressure is brought about by the 

 interactivity of these two antagonistic systems. 



The evidence which these observations supply of the almost 

 ubiquitous occurrence of cholin in the animal economy, has largely 

 diminished the importance of Lohmann's discovery. The 

 presence of comparatively large quantities of cholin in the supra- 

 renal cortex can hardly be regarded as proof of the production of 

 cholin as a specific function of that tissue. It is far more probable 

 that cholin represents a product of the decomposition of the 

 phosphatides which all organs contain, and that the comparatively 

 large quantities of cholin which are present in certain tissues, 

 merely show that such tissues are very rich in those lipoids. These 

 phosphatides are very liable to hydrolytic decomposition, in the 

 process of which they give off cholin. The presence of cholin is 

 not a proof of its pre-existence under physiological conditions. 



But the physiological activity of cholin, and especially its 

 antagonism to adrenalin, requires more careful investigation. 

 Modrakowski showed that the cholin (Merck) of commerce brings 

 about a fall in blood-pressure and a slowing of the pulse, which 

 may be arrested by means of atropine ; that it also produces 

 increased salivary and pancreatic secretion as well as increased 

 secretion of urine; but that these results are wholly attributable to 

 products, resembling muscarin, of the decomposition of cholin, 

 and more particularly to trimethylamin. Pure cholin is a com- 



