194 



METABOLIC HORMONES 



like the dog, where STH acts as an endocrinokinetic hormone 

 stimulating the secretion of glucagon, the actual diabetogenic 

 hormone, from the pancreas. No mention of glucagon has been 

 made in relation to this work on the chick; but the pancreas of 

 some other birds contains large amounts (Miller and Wurster, 

 1959). 



Mammalia. A striking difference between different mammals 

 occurs in respect of their diabetogenic hormones. In some carni- 

 vores, including the dog and cat, but not the ferret, the main 

 hormone that increases the blood glucose is glucagon, secreted 

 by a cells in the islets of langerhans (§ 2.222). In the rat and in 



GLUCOSE 



PHOSPHATE 



Ad. cortex 

 ACTHf 



GLUCOSE - 6 -PHOSPHATE 



PYRUVIC ACID 



LACTIC ACID 



Fig. 5-8. Diagram to show some of the hormones believed to 

 facilitate chemical transformations in the intermediary metabolism 

 of the rat, Rattiis. In the dog, Canis, and some other carnivores, 

 the diabetogenic action of the adrenal cortex, Ad. cortex*, stimu- 

 lated by ACTH*, is replaced by that of glucagon stimulated by 

 STH. ATP is adenosine triphosphate, an enzyme and not a hor- 

 mone (from Ebling, 1951, and Fieser and Fieser, 1950). 



man, the main hormone having this action is hydrocortisone 

 from the adrenal cortex. This has interesting repercussions in 

 experimental work, since the cortex is stimulated by ACTH from 

 the adenohypophysis (§ 4.231), and glucagon by the "growth" 

 hormone, STH, from the same source (§ 4.222) ; it follows that 



