THE PITUITARY BODY 



mal dogs. According to Houssay and Mazzocco (1922), the 

 important non-protein nitrogenous constituents of blood are 

 present in about the same concentration in the blood of 

 normal and of hypophysectomized dogs. 



Some of the most important changes in metabolism (par- 

 ticularly the basal metabolism) after hypophysectomy are 

 discussed in chapter vii. It is appropriate to mention here, 

 however, studies of the protein metabolism in hypophysec- 

 tomized and normal dogs. If the hypophysectomized dog is 

 starved, the excretion of nitrogen is considerably reduced 

 (one-third to two-thirds) in comparison with that of the 

 starved normal dog (Aschner, 1912; Braier, 1931, 1933)- 

 Normal and hypophysectomized dogs fed regularly, however, 

 excrete in 24 hours about the same amount of nitrogen in the 

 urine; but during the first 8 hours the operated dogs excrete 

 less (Braier). The hypophysectomized dog is thought to 

 excrete more allantoin and less uric acid and purine bases in 

 comparison with the normal dog (Braier, 1933). The admin- 

 istration of protein to the hypophysectomized dog produces 

 a relatively greater specific dynamic action because the basal 

 metabolic rate of the hypophysectomized dog is considerably 

 less than normal (Artundo, 193 1). 



From observations of the effects of extirpation of the an- 

 terior or posterior lobe of the pituitary body, and from studies 

 of the effects of extracts of the various parts of the pituitary, 

 it may be concluded that probably all the changes so far de- 

 scribed are due to the removal of the pars glandularis. There 

 is no evidence that the pars intermedia is physiologically im- 

 portant in the dog. The pars tuberalis is said to undergo 

 hypertrophy after hypophysectomy (Koster, 1928; Koster 

 and Geesink, 1929), but this has been denied (Karlik and 

 Robinson, 1931). In the case of the active principles which 

 can be extracted from the pars neuralis, some investigators 

 have observed in hypophysectomized dogs changes which 

 they attributed to the removal of the posterior lobe. For the 



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