THE PITUITARY BODY 



Although Aron (1930, 1931, 1933-34) has produced thy- 

 roid stimulation by extracts of normal urine and serum, 

 others have failed to confirm this finding, particularly in 

 cases of Graves's disease (Del Castillo and Magdalena, 1931; 

 Krogh and Okkels, 1933-34; and Smith and Moore, 1933). 

 According to one of the latest reports, that of Loeser (1934), 

 injected thyrotropic hormone is excreted in a potent form by 

 the kidneys (rabbit). Loeser as well as Schittenhelm and 

 Eisler (1935) have also studied other aspects of the metab- 

 olism of the thyrotropic hormone. 



The assay of the thyroid-stimulating hormone. — For conven- 

 ience and specificity, probably the response of the young 

 guinea pig's thyroid is best as a means of assaying the thy- 

 rotropic hormone. The histologic changes may be deter- 

 mined after administering minimally effective doses, dis- 

 tributed over several days, to littermate animals kept under 

 exactly similar conditions. The control member of a litter- 

 mate pair may be given nothing or a standard preparation. 

 Assay by means of weight-changes in the thyroid certainly re- 

 quires larger doses and is said to be less reliable. Aron (1932), 

 Del Castillo (1932), and Kleine (1932) have described the 

 technique of the test and the precautions which they believe 

 to be necessary. The acetonitril test of Reid Hunt, the effect 

 on metabolism, and the effect on metamorphosis in amphibia 

 have also been employed. These three methods are indirect 

 (i.e., indicate an increased rate of thyroid secretion or the 

 presence of thyroid hormone in the material tested) and ap- 

 pear a priori to be less specific and more variable than the de- 

 termination of the effect on the guinea pig's thyroid. Accord- 

 ing to Oehme, Paal, and Kleine (1932), however, some indi- 

 rect methods are the most sensitive. (See also Grab, 1932; 

 Kleine and Paal, 1933; Oehme, Paal, and Kleine, 1933; 

 Schoedel, 1933; Anderson and CoUip, 1934; and Atwell, 



1934-) 



In several recent reports more attention has been given to 



[274] 



