Age and Renal Disease 



255 



adiposity and abnormal fat metabolism. If the normally-fed 

 rats with one kidney were to develop the same pathological 

 renal changes as the overfed rats with two, then it would be 

 reasonable to attribute the lesions to some effect associated 



with overloading. They did develop the lesions at the same 

 time as the obese rats, at an average age of 15 months. 

 Table III illustrates the changes in composition of the kidneys 

 12 months after carrying out each type of operation on three- 



Table III 



Composition of the kidneys of obese animals, or of animals 



WITH ONE kidney REMOVED, TWELVE MONTHS AFTER OPERATION 

 (operated at three MONTHS OF AGE) 



Group 



Control (not operated on) 

 Kidney removed 

 Obese 



Total 

 nitrogen 

 {mg. per 

 kidney) 



34-9 

 73-5 

 75-9 



RNA 



phosphorus 

 {mg. per 

 kidney) 



0-749 

 1-429 

 1-972 



DNA 



phosphorus 

 {mg. per 

 kidney) 



0-239 

 0-695 

 0-785 



month-old animals. Note that in each case the final renal 

 breakdown occurred quite quickly and that rats killed during 

 the period between four months and a year old had large but 

 otherwise normal kidneys. 



The period of latency is interesting, because in subsequent 

 experiments it became shorter with increasing age of the 



