Specific Affinity of Thyroid Cells for Iodin. 133 



by the Ringer's solution, while with the spleen and kidney none 

 was held. It was also noted that the amount of KI taken up by 

 a thyroid does not depend on the amount (concentration) of KI in 

 the perfusate. Relatively much less was taken up when 40 mgm. 

 were added to a 75 c.c. perfusate than when 10 mgm. were used. 

 The most interesting observation was that the more marked the 

 hyperplasia (i. e., the less iodin in the gland originally), the more 

 iodin was taken up and also the more rapidly it was taken up, just 

 as in the case of in vivo experiments. 



Thus grouping the glands according to their anatomical 

 structure, it was found that from 10 mgm. KI the marked hyper- 

 plasias increased their iodin contents over 1,000 per cent.; the 

 moderate hyperplasias increased over 200 per cent.; the colloid 

 early hyperplasias increased over 100 per cent.; and the pure 

 colloid glands about 20 per cent. This is shown more in detail 

 in the following tabulation: 



Anatomical Condition of Gland. 



No. of 

 Cases. 



Average 

 Iodin* per 

 Gm. Before 

 Perfusion. 



Average 

 Iodin per 

 Gm. After 

 Perfusion. 



Average 

 Increase in 

 Iodin per 

 Gm. 



Per Cent. 

 Increase in 

 Iodin. 



Marked hyperplasia 



5 



0.07 



0.79 



0.72 



1,000 + 



Moderate hyperplasia 



3 



O.23 



O.77 



0-54 



200 + 



Colloid early hyperplasia .... 



3 



O.47 



1. 14 



O.67 



100 + 





3 



1.03 



1-23 



0.20 



19 + 



Thyroid glands undergo autolysis in a few hours after removal 

 from the body especially if kept around the body temperature. 

 This is recognized on microscopic examination by a desquamation 

 of the alveolar epithelium. It was found that all such glands not 

 only fail to take up iodin from the perfusate, but lose iodin to the 

 perfusate, a finding that we interpret as meaning that the dead 

 cells have lost the power of storing iodin, or that the taking up 

 of iodin by the thyroid is a property of surviving cells. Studies to 

 determine whether the iodin taken up is as active pharmaco- 

 logically as the naturally iodized thyroglobulin have not been 

 completed. However, since the amount of iodin taken up by a 

 given perfused gland may be independent of its concentration in 

 the perfusate, and since the amount taken up and the rapidity 

 of its storage varies directly with the degree of active hyperplasia, 



♦Expressed in milligrams per gram of dried gland. 



