THE PITUITAKY GLAJSTD 55 



the milk has accumulated. "The pituitrin," says 

 Macleod, "stimulates the muscular fibers of the 

 ducts of the mammary glands, thus squeezing out 

 the milk contained in them." 



One other property of this pituitrin must be re- 

 ferred to. We have noticed that partial removal 

 of the pituitary in animals, giving rise to hypo- 

 pituitarism, is followed by an increased capacity 

 for carbohydrate storage (in the shape of fat). 

 We find, on the contrary, that injection of pituitrin 

 decreases sugar tolerance to such an extent as to 

 give rise to sugar in the urine. Evidently it is 

 the lack of a sufficient quantity of this hormone in 

 the animal suffering from hypo-pituitarism that 

 gives rise to an increased sugar tolerance. All of 

 which is in favor of the view that pituitrin, like 

 adrenaline, like the pancreatic hormone ( see under 

 pancreas), plays a part in carbohydrate metabo- 

 lism, though it by no means follows that the three 

 parallel one another in their action. 



Pituitrin not a chemically pure product. We 

 have given the name "pituitrin" to the hormone (or 

 hormones) present in the posterior lobe of the 

 pituitary. It should now be made quite clear that 

 this hormone has not been isolated in the pure state 

 at all ; that "pituitrin," of which there are several 

 varieties on the market, is merely a concentrated 

 extract of the posterior portion of the lobe, usually 

 obtained by first getting rid of the protein present 



