HORMONES 



sidiary perhaps to the problem of mechanism of action are the 

 problems of inhibition and synergism in hormone action. Ap- 

 parently straightforward examples of hormone antagonism may 

 be cited : the inhibition of androgens by estrogens, the antago- 

 nism between pituitary growth hormone and AGTH in a num- 

 ber of their effects, the anti-insulin effect of certain cortico- 

 steroids, diuretic and antidiuretic hormones. Synergism is less 

 easy to exemplify — estrogen and progestin seem to synergize in 

 certain effects, not in others; and augmentation of androgen 

 stimulation has been observed with thyroxin administration; a 

 horse pituitary extract in itself inactive appears to sensitize the 

 adrenal to ACTH action. When one examines these types of 

 hormone interaction somewhat more closely, it becomes difficult 

 to be certain that the same process is affected by the interacting 

 hormones. Thus androgen and estrogen both stimulate pros- 

 tate growth ; the former acts upon the secretory tissue, the latter 

 on the utricle ; yet estrogen is employed in prostatic disease as an 

 androgen antagonist. Estrogen sensitizes the uterus to pro- 

 gestin action and is thus synergistic, but large estrogen doses may 

 actually inhibit pseudopregnant proliferation due to proges- 

 terone. The crux of the matter lies in the identification of the 

 specific chemical processes labile to the various interacting hor- 

 mones, and this, as we have said before, still eludes us. 



Hormone Therapy 



I have scarcely remarked on the therapeutic actions of the 

 hormones, particularly their role in affecting various pathologi- 

 cal processes. The earliest uses of hormones in therapy were for 

 replacement in obvious cases of deficit. The wide usage of 

 estrogen in the menopause is considered replacement therapy, 

 as is insulin for the control of diabetes, thyroid in hypothyroid- 

 ism, and corticosteroid in Addison's disease. With the advent 

 of new and more potent preparations of various types and partic- 

 ularly with the discovery of the antiphlogistic actions of ACTH 

 and corticosteroids, experimental investigations of hormone ef- 



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