THE EFFECTS OF HYPOPHYSECTOMY 



and asthenia of hypophysectomized toads (Houssay, 1933), 

 as well as the lessened work capacity of the gastrocnemius of 

 hypophysectomized frogs (Deuticke, 1931), may be related 

 to the atrophy of the adrenal cortex resulting from the re- 

 moval of the pituitary. 



The significance of the atrophic changes in the thyroid 

 gland of hypophysectomized amphibia is discussed in chap- 

 ter vii. 



From experiments with toads there is considerable evi- 

 dence of the importance of the pars glandularis in carbohy- 

 drate metabohsm. Houssay and his co-workers/ who per- 

 formed their experiments with B. arenarum and B. marinus^ 

 found that hypophysectomy was followed by a reduction in 

 the concentration of the blood sugar and of the hepatic gly- 

 cogen. Moreover, insulin induced a more marked degree of 

 hypoglycemia than in normal animals. In toads rendered 

 diabetic by pancreatectomy, the subsequent removal of either 

 the pars glandularis or the entire pituitary aboHshed the gly- 

 cosuria and reduced the concentration of the blood sugar. 

 Zwarenstein and Bosnian (1932) hypophysectomized the 

 clawed toad, X. laevis. As a result of the operation, the con- 

 centration of the blood sugar was not changed; there was, 

 however, less elevation of the blood-sugar concentration, due 

 to the injection of glucose, than in normal animals. 



A striking hypertrophy of the fat body is found in hypo- 

 physectomized amphibia, without relation to the sex or to 

 the age (larval, immature, or adult) at which the gland is 

 removed. 



Allen (1916) and Smith (1916) were the first to call atten- 

 tion to the striking change in the pigmentation of the tadpole 

 following hypophysectomy (silvery appearance, albinism. 

 Fig. 45). Apparently Adler (1914) did not remove all the 

 pars buccalis in his operations (Fig. 43). Further studies of 



■* Houssay, Mazzocco, and Rietti (1925); Houssay and Biasotti (1930-71); Hous- 

 say, Di Benedetto, and Mazzocco (1933). 



[39] 



