B. A. HOUSSAY 



instances (Geschickter and Byrnes). Some estrogenic hormones have 

 curious tumorigenic actions on the guinea pig, while other hormones 

 can prevent this action (Lipschiitz). 



Benign and malignant tumors of the endocrine glands can pro- 

 duce exaggerated quantities of hormones, as shown in cases of hyper- 

 thyroidism, hyperparathyroidism, hyperinsulinism, acromegalia or 

 giantism, and some adrenal, ovarian, and testicular tumors. Complex 

 effects result from the action of adrenal tumors: They may exert either 

 virilizing or feminizing actions, influence metabolic phenomena, alter 

 the body shape, or modify arterial blood pressure. The ovarian tumors 

 also produce varied effects such as feminizing or virilizing actions. Less 

 familiar is the humoral mechanism by which the malignant tumors af- 

 fect the metabolism of the whole organism. 



Specificity 



Endocrine glands and hormones have considerable specificity 

 of action. The ovary stimulates the development of the feminine sexual 

 characters, and the testicle that of the male sexual characters, as can be 

 demonstrated by castration, which prevents their development or 

 provokes their regression in both sexes. Conversely, the ovarian graft, 

 or the administration of estrogenic hormones, develops the feminine 

 characters in either castrated or entire animals. In the same manner, 

 testicular grafts or androgenic hormones develop the masculine char- 

 acters in either male or females, whether castrated or not. 



Each hormone produces its characteristic action upon diverse 

 animal species. Thus, the insulin of a given animal produces hypo- 

 glycemia in all mammals. It is also a rule that the hormone extracted 

 from an animal is active in all other species of mammals. Thus, 

 insulin extracted from a variety of mammals produces hypoglycemia in 

 the rabbit, and insulin from bovine origin is active on all the verte- 

 brates on which it has been tried. But some rare exceptions are known. 

 Thus, gonadotropins from mammals have no effect on the gonads of the 

 toad, Bufo arenarum, the cause of the anomaly being unknown. 



Some hormones are elaborated by more than one gland. For 

 example, adrenalin is secreted by the chromaffin tissue but also exists 

 in the cutaneous poison of the toads. The estrogenic hormones are 

 found in the ovary, placenta, and adrenal cortex; and it is remarkable 



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