THE PITUITARY BODY 



complete development of diabetes insipidus. Generally, it 

 has been found extremely difficult to produce diabetes in- 

 sipidus after complete hypophysectomy, whereas, if the pars 

 glandularis is intact, the suppression of posterior-lobe secre- 

 tion readily produces that condition/'' (Also, if diabetes in- 

 sipidus has been produced, it can be abolished by removal of 

 the pars glandularis.) Most observations indicate that the 

 thyroid gland also must be intact. However, it is not certain 

 that the diuretic principle of the anterior pituitary is identi- 

 cal with thyrotropic hormone. 



Diuresis-inhibiting hormone facilitates the excretion of cer- 

 tain cations and anions, especially Na and CI. Future work 

 will have to decide what is the best interpretation of this 

 phenomenon in terms of the physiological importance of the 

 hormone. 



Whether or not the vasopressor hormone is physiologically 

 important because of its cardiovascular effects is not known. 

 Recently it has been shown that the hormone probably is 

 liberated by stimulation of the central end of a vagus nerve. 

 Its possible clinical significance in disorders like hypertension 

 and, especially, eclampsia, however great it may be, has not 

 been demonstrated. 



In view of the highly specific action of the oxytocic princi- 

 ple on the uterus, it is to be expected that new observations 

 on its importance in normal parturition will be gathered. 

 At present it appears that the hormone, i.e., the pars neu- 

 ralis, is not necessary for parturition. It is possible that par- 

 turition in normal animals may be greatly facilitated by its 

 action, perhaps in synergism with oestrogen. 



Although changes in the metabolism of carbohydrates can 

 be produced by posterior-lobe extracts, it is not possible to 

 state whether these effects are physiologically important. 



'•• It is to be hoped that older observations indicating that diabetes insipidus 

 can be produced by hypothalamic lesions after complete hypophysectomy will 

 be either disproved or confirmed, so that they can be evaluated. 



[ '^~<r- ] 



