THE ANATOMY OF THE PITUITARY BODY 



ever, the young are removed, the pars glandularis assumes 

 the appearance characteristic of gonadectomized animals (in- 

 creased numbers of basophils, "castration-cells"). Kraus 

 (1935) has advanced the opinion that the "pregnancy-cells" 

 of the pars glandularis, growing initially because of placental 

 stimulation, secrete the lactogenic hormone which is released 

 into the circulation after the expulsion of the placenta. He 

 believed that suckling is the stimulus responsible for the con- 

 tinued secretion of the lactogenic hormone by these cells. 



Characteristic changes in the anterior pituitary following 

 gonadectomy can be consistently observed in the rat and 

 have already been described in the former volume. These 

 changes chiefly involve the basophils which increase in num- 

 ber and later hypertrophy and become vacuolated. Such 

 basophils containing a single large vacuole have been named 

 castration-cells. In other animals, such as the guinea pig, 

 contradictory descriptions of the changes in the pars glandu- 

 laris following gonadectomy continue to appear. Unlike 

 Severinghaus, Nelson (1935) declared that gonadectomy (or 

 cryptorchidism) is followed by a slight but definite increase 

 in the percentage of basophils in the guinea pig's anterior 

 pituitary; however, Nelson agrees that castration-cells of the 

 murine type are rare. An increased amount of colloid has 

 been described in other studies of the pituitary of gonadec- 

 tomized animals. Nelson mentions that thyroid-like follicles 

 containing colloid are prominent in the anterior pituitary of 

 gonadectomized or cryptorchid guinea pigs. Tuchmann 

 (1937), who also studied the pituitary of gonadectomized 

 guinea pigs, observed an entirely different change — i.e., a 

 progressive, marked increase in the proportion of oxyphils. 

 Both Nelson and Tuchmann were able to reverse the changes 

 caused by gonadectomy by injecting oestrin. The reader is 

 referred to the earlier volume for a description of anterior 

 pituitary changes attributed to gonadectomy or injury of the 

 gonads in man and other mammals. 



The other recent reports deal with the correction or re- 



[17] 



