THE PITUITARY BODY 



fects of implantation or removal of the pituitary or its parts 

 in larvae of T. taeniatus, carnifex, and alpestris, the reader is 

 referred to the articles of Klatt (1931, 1933). Successful 

 transplantation of the adult pituitary into larvae q>{ Amblys- 

 toma tigrinum (age about that of sexual differentiation) is 

 followed by a marked stimulation of the testis but not by an 

 effect on metamorphosis (Burns, 1934). Uhlenhuth and 

 others (1934) produced precocious metamorphosis in larvae 

 of this same salamander by repeatedly injecting anterior 

 pituitary extract; they believed that metamorphosis occurred 

 earlier if either pilocarpine or epinephrin was also adminis- 

 tered. By itself, neither drug had any effect. 



Magdalena (1935) found that hypophysectomy prevented 

 compensatory hypertrophy of the thyroid in the toad (spe- 

 cies?). Larson (1918), Rogers (1918), and Hoskins and Hos- 

 kins (1920) all reported that hyperplasia of the anterior lobe 

 appeared after thyroidectomy in frogs, toads, and tadpoles. 



During normal metamorphosis the pituitary is richer in 

 "thyrotropic" hormone, as shown by the experiments of 

 Allen (1932) who could produce metamorphosis by homo- 

 transplants of the pituitaries of metamorphosing tadpoles 

 {Bufo halophilus) but not by transplants taken from non- 

 metamorphosing larvae. The weight of the experimental evi- 

 dence overwhelmingly favors the view that functioning thy- 

 roid tissue must be present if extracts or implants of the an- 

 terior pituitary are to produce metamorphosis. Hoskins and 

 Hoskins (1920) and Hogben (1923), who used a commercial 

 anterior pituitary preparation which apparently contained 

 thyroid gland (Smith and Cheney, 1921), alone reported that 

 thyroidectomy did not prevent metamorphosis following the 

 administration of anterior pituitary. All investigators except 

 Hoskins and Hoskins have found that the feeding of anterior 

 pituitary is ineffective and that the parenteral administration 

 of tissue or extracts is necessary. Many investigators have 

 produced metamorphosis in normal or hypophysectomized 



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