THE PITUITARY BODY 



the vasopressor substances. Kamm and his collaborators 

 (1928) went much further. Not only were they able to effect 

 a much more complete separation of the oxytocic and the 

 pressor principles, but they also could account quantitatively 

 for the oxytocic and pressor "potency" in the crude ma- 

 terial with which they started. On the basis of their own 

 work and that of others they concluded that these two active 

 principles were amines. In terms of international standard 

 power their oxytocic substance had been concentrated one- 

 hundred- and-fifty fold, and their vasopressor substance, 

 eighty fold. Both substances appear to have a molecular 

 weight of about 600 (Kamm, 1928). Du Vigneaud and his 

 collaborators (1933) investigated some of the chemical differ- 

 ences between purified oxytocic principle (500 units per mg.) 

 and vasopressor principle (200 units per mg.). The oxytocic 

 principle appeared to contain about 9 per cent cystine (Sulli- 

 van-reaction), whereas the pressor principle contained scarce- 

 ly any; however, both principles contained about 3 per cent 

 sulphur. More tyrosine (?) in terms of phenolic groups was 

 found in the oxytocic fraction (14.3 per cent) than in the 

 pressor fraction (10.5 per cent). 



Stehle (1933-34) has also described a method of separating 

 in potent form the oxytocic and the pressor fractions. 

 Stehle's method is simpler than that of Kamm and others. 

 Some chemical properties of the oxytocic principle as well as 

 attempts to purify it are described in the papers of Gulland 

 and Newton (1932), Gulland (1933), Guha and Chakravorty 

 (1933), and Das and Guha (1933-34). 



As a rule the oxytocic and the pressor principles occur in 

 about the same proportion in the pars neuralis of the ox. 

 They dialyze through collodion membranes at about the same 

 rate (Smith and McClosky, 1924, and Kamm, 1928). They 

 are destroyed at about the same rate by acid (e.g., by boiling 

 in 0.5 per cent HCl) or by alkali (e.g., i or 2 N NaOH at 

 room temperature). Fractionally sterilized and sealed in 



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