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The Action of Pituitary Extracts upon the Kidney. 

 By E. A. Schafer, F.R.S., and P. T. Herring. 



(Received May 2,— Read May 3, 1906.) 



(From the Physiological Laboratory of the University of Edinburgh.) 



(Abstract.) 



Intravenous injections of saline extract of the infundibular part of the 

 pituitary body produce dilatation of kidney vessels accompanied by 

 increased flow of urine ; i.e., the extract has a diuretic action.* 



With the first injection this result is accompanied by the rise of blood- 

 pressure and contraction of systemic arteries described originally by Oliver 

 and Schafer,! and since confirmed by various observers. 



With subsequent injections (if the first injection were not too small in 

 amount) administered within a certain interval of time after the first one, 

 the diuresis is usually attended not by a rise of blood-pressure,+ but by a 

 fall (depressor effect).§ This fact furnishes evidence that the diuresis is 

 independent of the effects upon blood-pressure and leads one to suppose 

 that it is produced by a special constituent of the extract. 



This conjecture is confirmed by the result of treating the extract with a 

 peptic digestive fluid or with hydrogen peroxide. These agents tend to 

 abolish the rise of blood-pressure which is produced by a first injection, but 

 leave the diuretic effect of the extract unaltered. Reducing agents and the 

 action of tryptic digestive fluid leave all the active constituents of the 

 extract apparently unaffected. 



The diuretic as well as the pressor and depressor constituents of the 

 extract are not destroyed by boiling. They dialyse through parchment 

 paper. They are insoluble in absolute alcohol and ether. 



Occasionally, especially with large doses of the extract, the diuretic effect 

 fails to show itself. This appears to be due to the kidney vessels 

 participating in the general vascular constriction which is caused by the 

 extract. More often such constriction of renal vessels is only temporary, 

 and gives place to dilatation with free flow of urine. 



Hypodermic injections produce effects similar to those caused by intra- 



* See Schafer and Magnus, ' Physiol. Soc. Proc., : p. ix, in 1 Journ. Physiol.,' vol. 27, 

 1901. 



t ' Journ. Physiol.,' 1895, vol. 18. 



i W. H. Howell, ' Journ. Exp. Medicine,' vol. 3, 1898. 

 § Schafer and Vincent, ' Journ. Physiol.,' 1899, vol. 25. 



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