THE GROWTH-PROMOTING HORMONE 



the involution of the thymus took place more rapidly in the 

 fowls which received anterior pituitary. The results of Max- 

 well (1916), who fed fresh ox pituitary and lamb thymus to 

 growing fowls, were similar. 



In spite of earlier reports/ some of which were recognized 

 by the authors themselves as being negative or inconclusive, 

 there appears to be no foundation for the belief that growth- 

 acceleration may be caused in mammals by the feeding of the 

 pituitary or the pars glandularis or extracts of these. Aldrich 

 (1912), Sisson and Broyles (1921), Drummond and Cannan 

 (1922), Evans and Long (1922), and C. S. Smith (1923) ob- 

 served no growth-acceleration in normal mammals. The 

 most conclusive experiments were those of Smith (1927) who 

 fed the pars glandularis of the ox to hypophysectomized rats; 

 the oral administration of two fresh anterior pituitaries each 

 day to each hypophysectomized rat was without effect on the 

 body-weight. Such rats promptly increase in size after the 

 parenteral administration of anterior pituitary tissue. 



THE EFFECTS OF THE PARENTERAL ADMINISTRATION 

 OF THE GROWTH-PROMOTING HORMONE 



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

 mone to amphibia. — Smith and Smith (1922-23) administered 

 intraperitoneally suspensions of different parts of the pitui- 

 tary body of the ox to hypophysectomized or normal tad- 

 poles. The hypophysectomized tadpole thereby could be 

 caused to grow even larger than normal tadpoles. In addi- 

 tion, the abnormal atrophic changes in the thyroid, adrenal 

 cortex, and epithelial bodies (parathyroids) were corrected. 

 All these effects were produced by suspensions of the pars 

 glandularis only. A more pronounced effect on growth was 

 caused by the portion made up of reserve and oxyphil cells; 



■* Goetsch (1916); Marinus (1919); Robertson and his co-workers (1916, 1919-20, 

 1923); Schafer (1909, 1912); and others. 



[8U 



