162 H. TUCHMANN-DUPLESSIS AND L. MeRCIER-PaROT 



experimental conditions certain hormones, such as the oestro- 

 gens, are capable of delaying or, on the contrary, of hastening 

 the ageing of the endocrines. It seems, therefore, as if modi- 

 fications in hormonal equilibrium are capable of influencing 

 the general process of development and ageing. During the 

 last two years we have tried to examine the problem of the 

 relationship between the endocrine glands and the somatic 

 development by modifying the endocrine balance of the 

 pregnant female. The results of two series of experiments are 

 given here, one on the action of the somatotrophic hormone 

 (STH), the other on that of cortisone. 



Somatotrophic Hormone 



The well-known part played by the anterior pituitary 

 in somatic development has led many authors to consider 

 somatotrophic hormone as a stimulant not only of postnatal 

 growth but also of embryonic development. That, at least, is 

 the conclusion reached by Teel (1926), Hain (1932), Sontag 

 and Munson (1934) and Watts (1935), who observed that the 

 injection of crude extracts of the anterior pituitary into 

 pregnant rats gave rise to foetal gigantism. Using the purified 

 hormone Hultquist and Engfeldt (1949), Engfeldt and Hult- 

 quist (1953), Nixon (1954) and Cotes (1954) also produced in 

 rats enormous foetuses weighing up to 7 and 8 g. However, 

 the injection of STH into pregnant females of other species, 

 such as the dog and the cat, gave inconsistent results (Young, 

 1946). 



The question of the foetal gigantism obtained with STH 

 has often been raised in connection with the large children 

 born of diabetic mothers, and highly ingenious interpretations 

 have been put forward to explain the exaggerated foetal 

 growth. However, it seems improbable that STH, due to its 

 high molecular weight, could cross the placental barrier, and 

 the possibility of stimulating embryonic growth with STH 

 seemed astonishing, and therefore we repeated the experi- 

 ments on the rat. 



