Effects of Injury of Pituitary 



103 



It was found by Cushing (in conjunction with Goetsch and Jacobson) 

 that immediately after the operation of partial hypophysectomy a temporary 

 glycosuria would at first usually ensue. This result is perhaps due to a 

 dislodgment of accumulated secretion and irritation due to the injury. The 

 effect, however, soon passes off, and is followed by the permanent condition 

 of increased tolerance for sugar. Animals which have acquired this tolerance 

 will suffer loss of the pancreas without becoming diabetic. Injury to the 

 posterior lobe or even its manipula- 

 tion is, probably for the same reason 

 (release of accumulated secretion and 

 possibly temporary irritation due to 

 the injury), often immediately fol- 

 lowed by marked glycosuria and also 

 by polyuria, which may persist long 

 after the glycosuria has disappeared 

 or may be present from the first with- 

 out glycosuria (diabetes insipidus). 

 In one case of such injury to the 

 pituitary in a dog operated upon by 

 me the amount of urine rose from 

 40 c.c. per diem to 230 c.c, and during 

 the following nineteen days remained 

 at an average of 119 c.c. In another 

 it rose from 110 c.c, the average of 

 eleven normal days, to 182 c.c, the 

 average of the eleven days immedi- 

 ately succeeding the operation. It 

 was, however, much higher than this 

 on the third, fourth, and fifth days, 

 averaging 266 c.c. Mere exposure of 

 the pituitary was found to have no 

 such effects. A case in man has been 

 recorded by Simmonds in which there 

 was a malignant tumour of the pars 

 nervosa extending to the pars inter- 

 media, with marked diabetes insipidus (10 to 19 litres of urine per diem). 

 This is probably a case of the cells of a malignant tumour assuming the 

 functions of the tissues they are growing from (see p. 33). 



It has been found by Cushing that stimulation of the cervical 

 sympathetic or of its superior ganglion causes diuresis ; he considers this 

 is brought about by provoking the secretion of the posterior lobe, since 

 stimulation of the superior cervical ganglion produces no effect if the 

 pituitary be first removed. He therefore concludes that secreting nerves 

 pass through this ganglion to the pituitary. Cushing also states that ex- 

 cision of the posterior lobe or separation of the stalk is sometimes followed 



Fig. 71. — Young dog, eight months old, four 

 months after removal of the greater part 

 of the pituitary body. (Cushing.) Notice 

 the tendency to adiposity, and the de- 

 ficient development of the sexuai organs. 



