PREPARATION OF CORTICAL HORMONE 235 



difficulty of properly collecting and preserving them has here- 

 tofore rendered their use impracticable. 



The adrenals rapidly undergo autolytic changes and the 

 cortical hormone is rapidly destroyed after death. To illus- 

 trate the course of this destruction various portions of a batch 

 of glands obtained from one source were extracted and assayed. 

 One portion of the glands was removed from the carcasses of 

 freshly slaughtered animals and dropped into liquid air. 

 These glands were then extracted and found to contain 500 rat 

 units (as defined in Chapter XVI) per kilo of the original whole 

 glands. A second portion of the glands was frozen with "dry 

 ice" at the abattoir and packed in this refrigerant for two days 

 before extraction. From each kilogram of these glands, an 

 extract containing 100 rat units was obtained. A third portion 

 of the glands was placed in the refrigerator of the abattoir and 

 sent frozen to the laboratory on the following day. The ex- 

 tract prepared from these glands contained only 10 rat units 

 per kilo of glandular material. A fourth portion of the glands 

 was sent unfrozen to the laboratory. The extract prepared 

 from this material was found to contain only a trace of the 

 hormone. 



The deleterious effects of poor preservation of adrenal glands 

 on the yield of the hormone are obvious from the experiment 

 just described. In order to ensure preservation of the hor- 

 mone, the glands should be ground into two and a half to three 

 times their volume of acetone immediately on removal from 

 the animal. 



The adrenal cortical hormone is firmly attached to the lipids 

 of the adrenal cells and is removed only when these lipids are 

 simultaneously removed. Hence attempts to extract the hor- 

 mone from the glands by the use of aqueous acid or alkaline 

 solutions have been unsuccessful. Dehydrating the freshly 

 ground glands in vacuo at a low temperature destroys the cellu- 

 lar structure and permits extraction of the hormone by water. 

 Unfortunately, this method of extraction is not practical. It 



