§ I EXAMINATION OF BITTERLING HYPOPHYSIS 47 



a. Cellular changes in the gortidottophic zone. 



For reasons which will be explained in detail in § 2, we 

 divided the hypophysis of the bitterling into lobus tuberalis, 

 anterior, intermedius and posterior. The so-called "gonado- 

 trophic zone" of the pars anterior was examined after dif- 

 ferentiation by azan staining, which turns acidophil cells 

 red, basophil cells blue, and chromophobe cells a pale-bluish 

 tint. The staining capacity of the pituitary cells is rightly 

 held to be related to the cellular function. 



On examining the hypophysis of a bitterling caught during 

 the winter months we noticed that its anterior lobe consisted 

 almost entirely of acidophil cells. Only a small number of 

 cells were of the basidophil or the chromophobe type. The 

 number of basophil cells, therefore, was far too small to play 

 an important part. The picture presented by the hypophysis 

 changed in a surprising way, however, when we examined 

 the fishes during their reaction to steroid hormones. Then, in 

 certain parts of the anterior lobe, large "islands" of cells 

 became suddenly, and pronouncedly, basophilic, whereas, 

 in the control-animal, only acidophil cells were found in the 

 same region (Fig. 44A). In addition to this, an estimate 



"*«^J^- 





Fig. 44A. Medial section through 

 hypophysis of Rhodeus amarus. 

 The dark parts are composed of 

 basophile cells. 





iO /,-> 





\ ? 



/'slcnds of basophil cells ' 



