THE EFFECTS OF HYPOPHYSECTOMY 



gland following hypophysectomy are discussed in chapter vii. 

 (Also see Figs. 46 and 47.) 



Phillips and Robb (1934) reported that the blood-sugar 

 concentration of fasting hypophysectomized rats was low 

 (35-50 mg. per cent). They also believed that the intestinal 

 absorption of glucose was less than that in normal rats and 

 that the rate of storage of glycogen in the liver and in striated 

 muscle was considerably slower than in normal rats. 



In rats, as in other animals, the adrenal cortex but not the 

 medulla becomes atrophic after hypophysectomy (see Figs. 

 50 and 51). The medulla, however, is not as large as that of a 

 normal animal if a considerable time has elapsed after hypo- 

 physectomy, but is normal in structure (Smith, 1930). Ac- 

 companying atrophy of the adrenal cortex, there occurs a 

 reduction both in the amount of fat and in the amount of 

 cytoplasm of the cortical cells. Perla (1935) observed hemor- 

 rhages in the zona reticularis of the adrenal cortex during the 

 first 2 weeks after the removal of the pituitary from adult 

 rats. He concluded that this change preceded an atrophy. 



The author is not aware of any study of the parathyroid 

 glands of hypophysectomized rats. 



Smith (1930) reported that the thymus of the hypophysec- 

 tomized rat (weight, 91-149 g. at the time of operation) un- 

 derwent a more rapid involution than that of the normal rat. 

 In normal and hypophysectomized rats killed months after 

 the operation, the absolute weight of the thymus of the hypo- 

 physectomized rat was about one-half that of the normal rat. 

 Opposite results were obtained by Richter and Wislocki 

 (1930), who described a marked hypertrophy of the thymus 

 in hypophysectomized adu/t rats. 



According to Wyman and tum Suden (1934), removal of 

 the pars neuralis of the rat affected neither the blood pressure 

 nor the susceptibility to histamine, whereas total hypophy- 

 sectomy was followed by a lowered blood pressure and an in- 

 creased susceptibility to histamine. Foster and Smith (1926) 



[57) 



