THE PITUITARY BODY 



served that the maximum effect on the growth of dwarfed 

 mice was obtained by administering a growth-promoting ex- 

 tract ("Phyone") which had been only partially purified and 

 contained lactogenic, thyrotropic, and gonadotropic hor- 

 mones. Moreover, some authors have reported success in ex- 

 tracting from the anterior pituitary a growth-promoting prin- 

 ciple free from gonadotropic hormone (Evans and others) or 

 gonadotropic and thyrotropic hormones (Collip, Selye, and 

 Thomson) or lactogenic and thyrotropic hormones (Dinge- 

 manse and Freud, 1935). 



Some years ago Smith pointed out that the growth which 

 occurred in hypophysectomized rats following the adminis- 

 tration of a crude anterior pituitary extract was accompanied 

 by no betterment of the atrophic changes in the thyroid, 

 adrenal glands, and gonads. Also, it is agreed that the growth 

 response to pituitary extract is not reduced as a result of 

 thyroidectomy; in fact, acromegalic-like changes in the bones 

 and joints of guinea pigs receiving anterior pituitary extract 

 may be more pronounced in thyroidectomized than in normal 

 animals (Silberberg, 1936; Silberberg and Silberberg, 1937). 

 Mortimer's observations (1937) suggested that thyroid ex- 

 tract or thyrotropic hormone tends to cause a loss of minerals 

 from certain bones, whereas growth-promoting extract may 

 bring about a sclerosis. According to Moon (1937), suitably 

 large doses of adrenotropic extract inhibit the somatic growth 

 of gonadectomized animals without clearly affecting the 

 growth of the spleen, kidneys, liver, and gastrointestinal 

 tract; therefore, his results are in agreement with the view 

 that effects on the adrenal cortex play no positive role in 

 the general growth-promoting effect of a pituitary extract. 



The only sensible verdict to render in answer to the plea 

 that the anterior pituitary elaborates (or does not elaborate) 

 a specific growth-promoting hormone is the Scotch verdict 

 of "not proved." Although the thyroid, gonads, and adrenals 

 undoubtedly are important in the regulation of growth, it ap- 

 pears unlikely that changes in the secretory performance of 



[34] 



