THE EFFECTS OF HYPOPHYSECTOMY 



sists for a longer time in hypophysectomized dogs (Aschner, 

 191 2; Koster, 1930), whereas others find that the gland re- 

 gresses more rapidly as a result of the operation (x'^scoli and 

 Legnani, 1912; Houssay and Hug, 1921 ; Kapran, 1932). The 

 latest report is that of Houssay and Lascano-Gonzalez (1934). 

 They stated that precocious involution of the thymus oc- 

 curred in three-fourths of dogs hypophysectomized at an age 

 of 6-10 weeks and killed 5 weeks to a year later. The atrophic 

 changes, if present, involved chiefly the cortex; only few 

 Hassall's corpuscles could be found. 



No change in the pineal body occurs after hypophysectomy 

 (Aschner). 



The blood pressure of the hypophysectomized dog is 20-30 

 mm. lower than that of the normal dog (130-135 mm. Hg). 

 It is not altered, however, by the removal of the pars neural- 

 is. After a hemorrhage (1.5 per cent of the body-weight), the 

 blood pressure returns to its former level after 45 minutes in 

 normal dogs, but only after 95 minutes in hypophysectomized 

 dogs (Braun-Menendez, 1932, 1934). 



Besides those already mentioned, other constituents of the 

 blood have been studied in hypophysectomized dogs. In 

 nearly every case in which observations have been repeated— 

 sometimes in the same laboratory — there are disagreements 

 in results. The exceptions are sodium and chloride, which are 

 said to be present in the normal concentration (Mazzocco, 

 1927; Marenzi and Gerschmann, 1935). The concentration of 

 potassium and magnesium in the blood is said either to re- 

 main unchanged after hypophysectomy (Mazzocco, 1927) or 

 to be reduced (Marenzi and Gerschmann, 1935). Similarly, 

 the concentration of inorganic phosphate has been reported 

 not to change (Mazzocco, 1927; Gerschmann, 1931; and 

 Marenzi and Gerschmann, 1935), or to fall (Kobayashi, 1931 ; 

 and Ichijo, 1934). Fukushima (1931) stated that the concen- 

 tration of total fatty acids, lipoid phosphorus, and cholesterol 

 in the blood was greater in hypophysectomized than in nor- 



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