THE PITUITARY BODY 



5. The epiphysis. — Engel(i936),as well as Kup (1936), con- 

 tinues to champion the view that a pineal secretion inhibits 

 the growth-promoting effects of anterior pituitary secretion. 

 However, the evidence which they are able to assemble does 

 not enable one to attach even hypothetical value to this be- 

 lief. Some observations suggest the opposite effect. For ex- 

 ample, Takacs (1935) fed dried calf epiphysis to young fowls 

 (10-35 ^^^g- P^^ day). The birds receiving epiphysis for 4 

 months weighed more than 200 per cent more than the con- 

 trols. The excess weight was striking (102 per cent) but less 

 pronounced after 5 months' feeding, when the experiment was 

 terminated. 



Deficiency of vitamins or minerals and the growth-promoting 

 hormone. — It appears that failure of growth due to a deficien- 

 cy of vitamin A or of the "growth factor" of casein cannot be 

 attributed to a failure in secretion of growth-promoting hor- 

 mone. This is indicated by the experiments of Margitay- 

 Becht and Wallner (1937). The authors produced growth 

 stasis in young rats by diets deficient either in vitamin A or 

 in the alcohol-ether extract of casein. In neither case did the 

 administration of anterior pituitary growth-promoting ex- 

 tract cause a resumption of growth. There remains, of course, 

 the possibility that the dietary deficiency had rendered the 

 tissues refractory toward the hormone. 



Orent-Keiles, Robinson, and McCoUum (1937) concluded 

 that a sodium-deficient diet, more than diets deficient in CI 

 or NaCl, interferes with growth in the rat. Whether or not 

 this change as well as others, particularly in the female or- 

 gans of reproduction, depends to an important extent on 

 changes in the anterior pituitary is not known. According to 

 Hove, Elvehjem, and Hart (1937), zinc appears to be an im- 

 portant factor in the secretion or peripheral action of a pitui- 

 tary hormone controlling (favoring) the movement and tone 

 of the digestive tract of the rat. With a deficiency of zinc in 

 the diet and therefore with a deficiency of this hypothetical 

 hormone, intestinal absorption is delayed and reduced so 



