Jane A. Russell ^23 



First, the following observations made in fasted rats are relevant to this 

 \ iew. Simple saline or alkaline APE maintain muscle-glycogen levels in fasted 

 hypophysectomized rats. In short fasts, liver glycogen and blood sugar may be 

 also maintained, but in fasts as long as 24 hours, no effect is observed on these 

 levels even though perfect maintenance of muscle glycogen is obtained. There 

 is no evidence of new formation of glucose, but only of maintenance of already 

 formed glycogen stores. These extracts also act on muscle glycogen in adrenal- 

 ectomized or adrenalectomized-hypophysectomized rats.'"' In contrast to the 

 effects of simple APE, however, adrenocorticotrophic extracts (containing up 

 to ten times the potency of adrenocorticotrophic factor as the simple APE) 

 given over sufficient time for adrenal hypertrophy to take place in hypophy- 

 sectomized rats, increase liver-glycogen and blood-sugar levels even above nor- 

 mal values. This type of activity is not evident in adrenalectomized animals.^ 

 These effects of the corticotrophic extracts are remarkably similar to those 

 obtained by Long and collaborators with cortical extracts in hypophysecto- 

 mized and normal fasted rats. In all cases, there is produced a large increase 

 in liver glycogen and blood sugar; btU the effects on muscle glycogen are much 

 smaller and more slowly obtained than those on liver glycogen, and they 

 appear to be the result of an overflow of the glycogen formed in the liver. 

 Actual new formation of carbohydrate is clearly seen, in conditions in which 

 it is not demonstrable Avith simple APE; as mentioned before, maintenance 

 of preformed carbohydrate only results when APE is given. When cortical 

 hormone alone is given to fasted hypophysectomized rats, less carbohydrate is 

 found, compared to the increase in nitrogen excretion, than is the case in nor- 

 mal animals treated similarly. That is, the usual greater disappearance of car- 

 bohydrate after hypophysectomy seems to persist even when massive amounts 

 of cortical hormone have been administered. Finallv, summation of the differ- 

 ent effects of adrenal hormone and APE is evident when both are given to 

 fasted hypophysectomized rats.'* 



Further support for the view that more than one active hormone is found 

 in APE lies in comparisons of the "adrenocorticotrophic" and of the "glyco- 

 static" potencies of these extracts. There appears from the results of Bennett" 

 to be a discrepancy some sixtyfold in magnitude, when the morphologic effects 

 of different APE on the adrenals are compared with their ability to maintain 

 muscle-glycogen levels. There is, however, a close correlation between the 

 amount of cortical repair and the blood-sugar levels obtained in hypophysec- 

 tomized rats treated with adrenocorticotrophic preparations. This work has 

 been repeated recently by Bennett wath even more potent adrenocortico- 

 trophic extracts, with the same results as before (personal communication). 

 Again, there has been a separation of the effects of these hormones on blood 

 sugar and liver glycogen from those on muscle glycogen. 



Sensitivity to insulin as a similarity between hypophysectomized and 

 adrenalectomized animals has been mentioned, as has the evidence for the 



