LIPID STORAGE UNDER ABNORMAL CONDITIONS 627 



by Ruch and co-workers. 524 In the case of man, the hypothalamic injury 

 results from some neoplastic or infectious disease which involves either the 

 diencephalon or the adjacent region, namely the pituitary gland. Identi- 

 cal symptoms result from any of these causes in the several species. 



The most remarkable circumstance in regard to this type of obesity is the 

 rapidity with which it develops. In the case of laboratory animals having 

 experimentally produced lesions in the hypothalamic region, a dramatic in- 

 crease in weight may occur within a few hours after the operation. Bro- 

 beck 380 states that an adult female rat may increase in weight by as much 

 as 15% during the first twenty-four hours after hypothalamic injury, and 

 may then continue to gain at ten times the normal rate for several weeks. 

 The body weight then plateaus, and may remain constant for many 

 months. 376-379 The period of rapid gain has been designated as the dynamic 

 phase, and the plateau as the static phase of obesity. 519525 When this con- 

 dition obtains in the human subject, obesity begins quite abruptly, and 

 may frequently be correlated with the signs and symptoms of a disease proc- 

 ess near the base of the brain. 



The most prominent symptom of hypothalamic injury is the obesity 

 resulting from the rapid weight gain. This is to be ascribed to the deposi- 

 tion of excess fat. Smith 375 recorded an experiment in which the surplus 

 fat amounted to 74% of the total carcass weight. The excess fat was dis- 

 tributed uniformly in the various fat depots, including the subcutaneous 

 tissues, the omentum, the mesenteries, the perirenal tissues and around the 

 pericardium. 376 The liver was twice its normal size, and contained ap- 

 proximately four times the normal content of neutral fat. The level of plasma 

 lipids was also elevated, especially following feeding. Moreover, Graef 

 et aZ. 526 reported cirrhosis of the liver in obese dogs with combined hypophy- 

 seal and hypothalamic injury. Several symptoms, other than the fat de- 

 position, occur in hypothalamic injury or in tumors of the hypophysis. 

 These include hypoplasia of gonads and genitalia, 380,510 ' 515 ' 516 ' 527 ' 528 which is a 

 prominent symptom in Frohlich's syndrome. Abnormalities in skin and 

 fur have likewise been observed in rats, probably because the animals are 

 unable to groom themselves as normal animals do. 529 In the case of dogs 

 the fur becomes soft and luxuriant. 526 The obese animals frequently die as 

 a result of vague non-specific diseases. 376 ' 519 ' 522 Generalized dilation and 



824 T. C. Ruch, H. D. Patton, and J. R. Brobeck, Federation Proc, 1, 76 (1942). 

 525 H. R. Rony, Obesity and Leanness, Lea & Febiger, Philadelphia, 1940, p. 47. 

 626 I. Graef, J. Negrin, Jr., and I. H. Page, Am. J. Pathol., 20, 823-855 (1944). 



527 M. J. Babinski, Rev. neurol, 8, 531-533 (1900). 



528 A. W. Hetherington, Endocrinology, 26, 264-268 (1940). 



629 A. W. Hetherington and S. W. Ranson, J. Comp. Neurol., 76, 475-499 (1942). 



