^22 Pituitary and Carbohydrate Metabolism 



less in adrenalectomized than in hypophysectomized rats, in spite even of the 

 lower metabolic rates of the latter. The adrenalectomized rats do not show 

 the high fasting RQ's of the hypophysectomized animals.'' After evisceration, 

 the rate of fall of the blood sugar is not so fast as in hypophysectomized rats, 

 and the muscle glycogen does not fall at all." Thus, the peripheral utilization 

 of glycogen does not seem to be increased in the absence of the adrenals as 

 it is after hypophysectomy. This difference is emphasized by the fact that the 

 amount of cortical hormone necessary to maintain normal carbohydrate levels 

 in adrenalectomized rats (without salt treatment) is very much less than the 

 amount of extract needed to affect hypophysectomized rats; the amount of 

 cortical extract sufficient for the maintenance of normal carbohydrate levels 

 in adrenalectomized animals is without effect in the absence of the hy- 

 pophysis.'"' ™ 



When adrenalectomized rats are fed glucose, there is relatively normal dis- 

 tribution of the absorbed carbohydrate, although some changes may be ob- 

 served. The liver-glycogen deposition is usually low, but not always quite 

 so low as in hypophysectomized rats. Muscle glycogen, as a fraction of the 

 absorbed carbohydrate, is nearly normal. There may be some increase in 

 carbohydrate disappearance over the normal, but it is certainly not of the 

 magnitude observed in hypophysectomized rats. (These remarks refer to ani- 

 mals given salt and kept in good condition by this means. Little deposition 

 of glycogen of any kind may be found in animals in acute insufficiency.) The 

 glucose tolerance may be normal. The rate of glucose absorption may be 

 normal or moderately subnormal, depending upon the particular experi- 

 mental conditions employed.* When this rate has been below normal, it has 

 not been restored, in the author's experience, by either APE or cortical hor- 

 mone therapy, indicating that it may have had a nonspecific origin. When 

 the rate has been normal, quite normal disposition of the absorbed carbo- 

 hydrate has been reported.'" '' "^ "' 



From a close examination of the data described above, obtained in operated 

 animals, there is an indication of a possible difference in the roles of the an- 

 terior pituitary and the adrenal— that the adrenal cortex hormone affects the 

 liver glycogen and thence the blood-sugar levels, as suggested by the similarity 

 between the effects of adrenalectomy and of hypophysectomy on these sub- 

 stances, but that the anterior pituitary has specific effects on peripheral glyco- 

 gen storage. This hypothesis fits quite well a corollary thesis, that the adrenal 

 hormone produces its effects by acting on the gluconeogenetic process in some 

 stage, and that the anterior pituitary affects peripheral carbohydrate utiliza- 

 tion directly, as indicated by its effects not only on muscle glycogen but also 

 on the RQ. This hypothesis, of course quite tentatively based on the ob- 

 servations above, has been supported by study of the actions of the extracts— 

 by a demonstration of two different types of action of the hormones. 



* MarrazP has presented evidence that the low ghitose absorption rates of adrenalecto- 

 mized rats are due to inanition. 



