THE RELATIONSHIP OF THE ANTERIOR 



PITUITARY TO THE THYROID AND THE 



ADRENAL CORTEX IN THE CONTROL OF 



CARBOHYDRATE METABOLISM 



IN THE PAST several years, the anterior pituitary gland has been shown to have 

 important functions in the control of the intermediary metabolism of carbo- 

 hydrate and of protein, and directly or indirectly in that of fat. The determina- 

 tion of the precise role of any hormone in metabolism is difficult, but in the 

 case of the anterior pituitary it is the more so because of the manifold activities 

 of this gland. Particularly, complications arise from the trophic control by 

 the anterior pituitary of two other endocrine organs which are known to affect 

 certain phases of metabolism— the thyroid and the adrenal cortex. Thus, the 

 removal of the hypophysis brings about extensive atrophy of these glands, and 

 extracts of the anterior pittutary contain factors which affect the activity of 

 these glands and which are to be separated, chemically or physiologically, 

 from those other factors which may exert direct effects on metabolic activities. 

 Much of the work of recent years which has sought to define the nature of 

 hormonal control of metabolism has of necessity been devoted to the inter- 

 relationships between the hormones of the anterior pituitary, thyroid, and 

 adrenal cortex. Since most of these studies have been in the field of carbo- 

 hydrate metabolism, this discussion will be confined to that subject. It must 

 be remembered, however, that whenever changes occur in the metabolism of 

 carbohydrate inevitably changes also are to be expected in fat and often also 

 in protein metabolism. These may be very important, or they may even be 

 primary to alterations in carlDohydrate metabolism; it is only because of a 

 scantiness of data bearing on the interrelations of the hormones in these fields 

 that they are inentioned here but briefly, as they seem related directly to the 

 topic in hand. 



The chief effects of the removal of the anterior pituitary gland or of treat- 

 ment with anterior pituitary extracts on metabolism are now familiar phe- 

 nomena and many phases of these subjects have been reviewed."""^ The otu- 

 standing facts may be again outlined here, before they are analyzed with 

 respect to the various hormonal factors affecting them. The first strong indica- 

 tion of a relationship of the anterior pituitary to carbohydrate metabolism 

 was the observation by Houssay, in 1924, of the remarkable hypersensitivity 

 to instdin of hypophysectomized animals. This discovery was followed by that 

 which is now called the Houssay effect— the amelioration of pancreatic dia- 

 betes by hypophysectomy. Then the diabetogenic effects of anterior pituitary 

 extracts were demonstrated— the induction of states simulating pancreatic dia- 



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