Chapter XVI 



THE ASSAY OF THE ADRENAL CORTICAL HORMONE 



No chemical method being as yet available for detecting 

 the cortical hormone, it is necessary to depend upon some 

 biological method for the assay of adrenal cortical extracts. 

 The accurate determination of such assays is extremely impor- 

 tant. Chemical studies on the hormone can only be made if 

 one possesses a relatively simple method of assay with which 

 to follow the effects of various manipulations. In therapeutic 

 applications of the hormone it is necessary to know the potency 

 of the extracts which are administered. Much of the confusion 

 which exists at present is a result of erroneous ideas as to the 

 hormonal content of a given extract. Thus, the observed 

 effects of a given extract may be attributed to its assumed 

 high potency, when, in reality, careful assay may demonstrate 

 almost the complete absence of the hormone in the extract. 

 The futile use of the same extract clinically may lead to the 

 erroneous conclusion that the cortical hormone is useless in 

 disease. 



The various methods suggested for assaying the adrenal 

 cortical hormone may be divided into three groups : 1) methods 

 based on the increased susceptibility of an adrenalectomized 

 animal (usually the rat) to a drug or abnormal physical condi- 

 tion; 2) methods based on some change in the chemical com- 

 position of the blood of adrenalectomized animals ; 3) methods 

 based on the determination of the amounts of hormone neces- 

 sary for maintaining normal physiological activities in adrenal- 

 ectomized animals. 



METHODS BASED ON THE DIMINISHED RESISTANCE 

 OF ADRENALECTOMIZED ANIMALS 



Perla and Gottesman 497 have suggested the increased sus- 

 ceptibility of adrenalectomized rats to histamine as the basis 



248 



