180 CORTEX 



adrenal tissue per se, for by treatment of an adrenalectomized 

 animal with an adequate supply of the cortical hormone, the 

 blood cholesterol may be maintained at its normal level. The 

 most probable explanation of the observed hypercholesteremia 

 observed in adrenal insufficiency is that it is a result of hepatic 

 dysfunction induced by the absence of the adrenal cortical 

 hormone. This hypercholesteremia is usually not manifested 

 until after other changes due to cortical insufficiency (such as 

 the increased non-protein nitrogen and the changes in the 

 inorganic constituents of the blood) have already occurred. 

 As we shall see later, the earliest changes evident in the blood 

 chemistry in insufficiency are probably due to renal dysfunc- 

 tion. The hypercholesteremia and hypoglycemia, both of 

 which are of later occurrence, are attributable, in the author's 

 opinion, to liver injury. The liver normally secretes choles- 

 terol and its esters into the bile and any interference with its 

 normal activity would tend to result in an elevation of the 

 cholesterol content of the blood. 



The claim, first made by Stewart 593 and by Landau, 376 that 

 the injection of cholesterol prolongs the life of adrenalecto- 

 mized animals, is based on too inadequate data to merit its 

 acceptance. In rats, Firor and the author were unable to 

 demonstrate a prolongation of life after the injection or oral 

 administration of either cholesterol or lecithin. 



NON-PROTEIN NITROGEN 



Marshall and Davis 438 demonstrated the rise in the non- 

 protein-nitrogen (particularly the urea) concentration of the 

 blood which follows adrenalectomy in cats. After the injec- 

 tion of urea or creatinine, much less of these substances was 

 excreted than in normal animals. These authors also observed 

 a diminution in the excretion of phenolsulphonephthalein and 

 concluded that normal kidney function is dependent upon the 

 integrity of the adrenals or upon the product of their se- 

 cretion. Subsequent writers have amply confirmed these 

 results. 264, 404, 630, 693, 704 



