90 



The Endocrine Organs 



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coid of the pituitary is comparable to that of those drugs which act as 

 specific diuretics upon the secreting cells of the kidney, as distinguished 



from those which pro- 

 duce diuresis by increas- 

 ing the water content 

 of the blood or by merely 

 increasing the general 

 blood-pressure. 



The diuretic action 

 of the pituitary autacoid 

 is not antagonised by 

 atropine. This may be 

 taken as a sign that 

 it does not act through 

 nerves or nerve-endings, 

 but directly upon the 

 kidney cells ; in this re- 

 spect also it resembles 

 the action of secretine 

 upon the pancreas. 



Effect on Secretion of 

 Cerebro-spinal Fluid. 

 It has been shown by 

 Weed and Gushing that 

 extracts of posterior lobe 

 also contain an autacoid 

 which stimulates the 

 flow of cerebro - spinal 

 fluid (fig. 63). This is 

 not dependent on in- 

 crease of blood-pressure, 

 for it may be accom- 

 panied by a fall instead 

 of a rise of pressure, and 

 by an increase in depth of 

 the respirations : the in- 

 creased flow of cerebro- 

 spinal fluid seems to 

 be independent of these 

 circumstances. 



Effect on Milk Secre- 

 tion. It was found by Ott and Scott that in the goat an injection of 

 pituitary extract into a vein greatly increases the quantity of milk which 

 can be drawn from the udder in a given time after the injection, as com- 

 pared with that which could be obtained in a similar period immediately 



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