THE EFFECTS OF HYPOPHYSECTOMY 



the pars glandularis of T. cristatus or other newts brings 

 about an abnormal cornification of the epidermis and an in- 

 terference with molting (Adams). This change is related to a 

 hypofunction of the thyroid (see chap. vii). 



The disturbances in the metabolism of water, which may 

 occur in hypophysectomized frogs or toads, are discussed 

 below in the section dealing with lesions of the hypothalamus. 



The effect of hypophysectomy on metabolism (oxygen con- 

 sumption and carbon-dioxide production) in amphibia is dis- 

 cussed in chapter vii. Charles's experiments with X. laevis^ 

 however, should be mentioned here. She found that the reduc- 

 tion in the oxygen consumption of operated toads was more 

 pronounced in completely hypophysectomized animals than 

 in those from which only the pars glandularis had been re- 

 moved. The respiratory quotient was often as high as 1.09 

 (normal toads, 0.82). In the skeletal muscle of hypophysec- 

 tomized toads {B. arenarum) after nerve section, the amount 

 of total phosphorus and of phospho-creatine is reduced (Ma- 

 renzi, 1933). In B. marinus, hypophysectomy has no effect 

 on the amount of glycogen in skeletal muscle (Houssay, Maz- 

 zocco, and Rietti, 1925). In another toad, B. arenarum, the 

 operation is followed by a bradycardia and apparently a re- 

 duction in the concentration of glycogen in the cardiac mus- 

 cle (Orias, 1934). The concentration of lactic acid in the rest- 

 ing skeletal muscle of the toad is not affected by hypophysec- 

 tomy; the amount present after indirect stimulation, how- 

 ever, is much greater in normal toads (129 mg. per cent) than 

 in those from which the entire pituitary {i;^ mg. per cent) or 

 the pars glandularis (88 mg. per cent) has been removed 

 (Marenzi, 1934). The concentration of calcium and of po- 

 tassium in the serum of X. laevis is lowered as a result of hy- 

 pophysectomy or removal of the pars glandularis (Hogben, 

 Charles, and Slome, 1931; Zwarenstein, 1933). Shapiro and 

 Zwarenstein (1933) found that an equally great reduction in 

 the concentration of calcium in the serum occurred after 



[41] 



