THE PITUITARY BODY 



whereas the portion made up of reserve and basophil cells 

 caused the greater effect on the atrophic thyroid. 



Blount (1930) transplanted one or two Anlagen of the pi- 

 tuitary (buccal and neural) in the region of the extremity of 

 salamander embryos {A. punctatum). As as result, growth 

 was inhibited chiefly because of a shortening of the tail. There 

 also occurred shortening and thickening of the extremities. 

 Grafts of the buccal ectoderm alone did not grow and differ- 

 entiate. Burns (1930), and Burns and Buyse (1931) used 

 young larvae of A. tigrinum in their experiments. Neither 

 pituitary transplants from adult axolotls nor the injection of 

 alkaline extracts of the pars glandularis of the sheep or the 

 ox caused much change in body-size. A few animals were 

 slightly longer and had a greater girth and larger heads. It 

 will be recalled that salamanders, subjected to hypophysec- 

 tomy after metamorphosis, may grow as rapidly as normal 

 salamanders. 



The ejects oj the administration of the growth-promoting hor- 

 mone to mammals. — Evans and Long (1921) were the first to 

 demonstrate that the growth-rate could be accelerated and 

 that gigantism could be produced in a mammal (in this case, 

 the rat) by the long-continued injection of a simple extract of 

 the pars glandularis. Smith (1927) later showed that an an- 

 terior pituitary extract could cause the resumption of growth 

 of hypophysectomized rats. Most of the observations of other 

 investigators have been made in animals (dog, guinea pig, 

 rabbit, rat, man, and mouse) in which the pituitary had not 

 been disturbed. It must be realized that the growth-promot- 

 ing hormone has not been separated as a pure substance; 

 therefore, some of the statements in the following pages may 

 require modification in the future. 



In the early experiments of Evans and Long (1921-22), 

 anterior pituitary tissue of the ox was triturated in a mortar 

 containing sand and Locke's solution. The supernatant fluid 

 obtained from this mixture was then injected daily into the 



[86] 



