THE PITUITARY BODY 



"thymocrescin" of Asher possesses no analogous growth-pro- 

 moting effect (Simon and Binder, 1932). A similar statement 

 can be made concerning prolan and extracts of other glands of 

 internal secretion.^ 



The part played by diet. — The detection or assay of certain 

 vitamins (A and the B group) may be chiefly based on the 

 failure of animals to grow. Unquestionably, in such cases of 

 experimental vitamin-deficiency, the physiology of the 

 growth-promoting hormone of the pars glandularis is dis- 

 turbed. Probably there are both "central" and "peripheral" 

 changes — i.e., perhaps the pars glandularis secretes inade- 

 quate amounts of the hormone or no normal hormone; if the 

 normal hormone is secreted, the growth-potentiahty of the 

 tissues may be so reduced that no response occurs. At pres- 

 ent it is impossible to say which of these conceivable changes 

 is the more important; but that the growth-promoting hor- 

 mone is involved in some way appears to be an incontestable 

 fact. 



If growth-promoting hormone is administered either to 

 normal or to hypophysectomized rats, the rate of growth de- 

 pends upon the adequacy of the diet (Bryan and Gaiser, 

 Thompson and Gaiser, 1932). However, no matter how ex- 

 cellent the diet, the hypophysectomized rat will not grow un- 

 less growth-promoting hormone is also administered. Bryan 

 and Gaiser concluded that the diet, more than the inherent 

 growth-potentiality, determined the degree of growth-accel- 

 eration produced by the injection of the growth-promoting 

 hormone into normal rats. It is not known what is the maxi- 

 mum possible growth-rate of the rat. By means of improve- 



* Parhon and his collaborators (1930, 1934), believed that the growth-promoting 

 hormone could be detected in the serum and urine of patients with acromegaly; 

 the data they offer are too few to support this belief. Van Dyke and Wallen-Law- 

 rence (1930) were unable to detect the hormone in either the serum or the urine 

 of the acromegalic subject. 



Wehefritz and Gierhake (1932) reported that, by means of an adsorption method, 

 extracts causing growth in normal or hypophysectomized rats could be secured from 

 the urine of pregnant women. 



[94] 



