REGULATION OF GROWTH 



these glands account for the growth-promoting eifects of an- 

 terior pituitary extract. Future worlc must decide the sig- 

 nificance of the lactogenic hormone in growth, as far as 

 growth is affected by the pituitary body. Also, without con- 

 firmation, it is hazardous to affirm or deny either that 

 "growth-hormone" free from lactogenic (and other) hormone 

 can be prepared or that a suitable combination of anterior 

 pituitary "hormones," with little effect separately, can imi- 

 tate all the growth-promoting effects of a suitable anterior 

 pituitary extract. Therefore, the reader should recognize 

 that the use of the term "growth-promoting hormone" in 

 other parts of this chapter and book is dictated by conven- 

 ience rather than by a belief that it deserves more than a 

 qualified acceptance. 



Recent reports on visceral or somatic abnortnalities caused by 

 hypophysial deficiency. — Schofield and Blount (1937) ob- 

 served that the removal of the anterior pituitary from larvae 

 oi Ambly stoma punctatiim is followed by a general reduction in 

 growth, including the growth in length of the digestive tract. 

 They believed that the latter change is causally related to the 

 former. The reports of other investigators, previously re- 

 viewed, indicated that hypophysectomy in larval or imma- 

 ture salamanders of a closely related species i^A. tigrinum) 

 does not significantly affect growth. Aubrun (1935) removed 

 the pars glandularis or the neurointermediate lobe from Bufo 

 arenarum and observed cutaneous changes — hyperkeratosis 

 and lessened secretion, or paling and capillary dilatation — re- 

 sembling those previously described by Giusti and Houssay. 



Only a few reports dealing with mammals need be con- 

 sidered here. Houssay and Lascano Gonzales (1935) studied 

 the effects of hypophysectomy on the dog's spleen. In the 

 young dog, splenic growth was reduced; in the adult dog, 

 splenic atrophy appeared to be associated with an increase 

 in the size of the splenic follicle and an increase in the number 

 of malpighian corpuscles. The authors considered that the 

 changes resembled those characteristic of senility. The re- 



[35] 



