THE PITUITARY BODY 



referred to the authors' pubHcations for a detailed account of 

 their findings, which include observations of the effects of 

 such an extract on other phases of bone-growth in normal 

 and ovariectomized animals. Mortimer (1937) carefully 

 studied the changes in bones, especially those of the cranium 

 of the albino rat, resulting from hypophysectomy or from the 

 administration of growth-promoting extract. His observa- 

 tions cannot be adequately summarized in a few words, but 

 should be read in the original communication by those who 

 are interested in the endocrine phase of bone-growth and 

 maintenance. 



It will be recalled that the principal gross biochemical 

 changes in the bodies of normal rats, receiving growth-pro- 

 moting hormone compared with littermates not so treated, 

 consist of a diminution in the percentage of "fat" and an in- 

 crease in the percentage of water, protein, fat-free dry tissue, 

 and ash. Lee and Ayres (1936) have recently studied some of 

 the similar biochemical aspects of hypophysectomy in sixteen 

 pairs of littermate rats, one of each pair being hypophysec- 

 tomized at a weight of about 210 gm. All the animals re- 

 ceived the same food in the same quantity. The weight loss 

 of the hypophysectomized rats was about 20 per cent greater 

 than that of the normal rats; however, the normal animals 

 lost more fat (60 per cent loss compared with 28 per cent 

 loss in operated rats).^ There was a 20 per cent loss of body 

 nitrogen in the hypophysectomized rats, whereas there was 

 no loss in the normal group. The percentage of creatine and 

 creatinine in the carcass was the same in both groups. In 

 general, the changes observed in hypophysectomized rats 

 were the reverse of those following injections of growth-pro- 

 moting extract. Lee and Ayres also studied a number of 

 nitrogenous constituents, both protein and non-protein, of 

 the liver. The only conspicuous changes were in the total 

 non-protein nitrogen, amino acids, and urea, all of which were 

 present in higher concentration in the liver of the hypophy- 



^ Substances extracted by ether. 



[^8 1 



