THE PITUITARY BODY 



vasopressor principle. In man the strilcing change produced 

 by 3-10 units is the appearance of large peristaltic waves 

 in the colon ("mass-peristalsis") culminating in defecation 

 (Isaac and Siegel, 1929; Rondelli, 1929; Oppenheimer, 1931). 

 The effects, of course, may be greatly modified depending 

 upon the tone and contents of the colon, Carlson (1930), who 

 studied patients after colostomy or ileostomy, concluded 

 that the injection of posterior-lobe extracts caused an in- 

 crease in the peristaltic movements both in the colon and in 

 the small intestine. 



The effects of the oxytocic and vasopressor principles on 

 the intestinal movements of dogs (usually unanesthetized) 

 are irregular and inconsistent. The activity of the small in- 

 testine has often been found to be inhibited as the result of 

 the injection of an extract. In some experiments, however, 

 the bowl activity appeared to be increased (e.g., Melville and 

 Stehle, 1934). 7 



The intestine of the rabbit appears to be more sensitive 

 than that of other animals (e.g., dog and cat). There is fair 

 agreement among different investigators that the important 

 effects are an increase in tone and a stimulation of peristalsis 

 especially in the distal part of the colon. There is evidence 

 that these changes are chiefly due to the vasopressor prin- 

 ciple.^ Among the divisions of the small intestine the ileum 

 appears to be more sensitive than either the duodenum or 

 the jejunum.^ 



'Dixon, 1923; Mcintosh and Owings (1928); Gruber and Robinson (1929); 

 Carlson (1930); Gruber and others (1931); Puestow (1933); and Quigley, High- 

 stone, and Ivy (1934). 



' Kaufmann (1927) concluded that a substance different from the oxytocic or 

 the vasopressor principle stimulated the isolated small intestine of the rabbit and 

 cat. 



"Zondek (1920); Gruber (1926); Gaddum (1928); Elmer and Ptaszek (1930); 

 Melville and Stehle (1934). For experiments in which the isolated intestine of the 

 rat and cat has been used, see Voegtlin and Dyer (1924); McDonald (1925); and 

 Gaddum (1928). 



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