274 C. N. H. LONG 



precursor of the steroid hormones has also been put forth by various 

 investigators but curiously enough no experiments to demonstrate that 

 it varied under conditions of increased secretion of the adrenal cortex 

 or gonads had been done. 



We therefore injected the highly purified preparations of adreno- 

 trophic hormone into rats and determined the cholesterol content of the 

 glands after various intervals of time (6). It was found that single in- 

 jections of this trophic hormone decreased the cholesterol content of 

 the adrenal by some 50% in 3 to 6 hours, while its return to normal 

 levels required many hours. Similar results were observed in hypophy- 

 sectomized rats, provided too long a time had not elapsed since the oper- 

 ation. The cholesterol content of a variety of other tissues was not 

 affected by such injections. Finally, exposure of animals to such stresses 

 as cold, burns, trauma or hemorrhage brought about similar alterations 

 in the adrenal cholesterol of normal rats but did not alter the level in 

 hypophysectomized animals. Evidently the natural secretion of adreno- 

 trophic hormone following such procedures can also be detected by the 

 changes in the cholesterol content of the adrenal. 



In reviewing these results it appeared entirely possible that the rather 

 long period, an hour or -more before the adrenal cholesterol fell signifi- 

 cantly, might be due to the fact that this substance acted as a reservoir 

 for the continual replenishment of the hormone itself and that other 

 substances in the gland might be more closely related to the actual secre- 

 tion. 



The adrenal cortex is also unique in its high content of ascorbic acid 

 (Vitamin C). Furthermore this gland and the corpus luteum are the 

 only tissues in which such a high concentration of the vitamin is found 

 along with a very high concentration of cholesterol in the ester form. 

 It is unnecessary to remind you that ascorbic acid was originally iso- 

 lated from the adrenal, although the reasons for its presence in such 

 large amounts were not known. Further study of the literature indicated 

 that as in the case of cholesterol the level of this vitamin in the adrenal 

 was subject to wide variations, it being notable that under conditions of 

 stress low values were found. 



Consequently, similar experiments were carried out with adreno- 

 trophic hormone and it was found that the ascorbic acid level of the 

 adrenal fell very promptly after the injection, reaching values of less 

 than fifty per cent of the original level within one hour (7). Indeed, a 

 significant decline could be detected within twenty minutes after injec- 

 tion. Exposure of normal animals to the types of stress mentioned 



