168 



JiM Kre^ek, et al. 



sodium and potassium after administration of a water load. 

 Males excrete a water load less well than females. 



In our experiments the excretion of a water load was the 

 same in infant rats as in the experiments of Heller (1952). 



Renal 

 water 

 loss 



Renal 



sodium 



loss 



Renal 



potassium 



loss 



Without prehydratlon 



With prehydratlon 



: ru 



/tEq/lOO g 

 ■450 



-300 



■150 



^Eq/100 g 

 450 



300 

 150 



h 



Fig. 1. The renal loss of water, sodium and potassium during the first three 



hours after administration of a water load (4-5 ml./lOO g. body wt.) to 



young rats aged 23 and 33 days without prehydration or with prehydration 



(2 • 5 ml./lOO g. body weight). 



There are no sex differences. There are, however, consider- 

 able differences between infant animals aged 23 and 33 days. 

 These can be seen in Fig. 1. Twenty-three-day-old animals 

 do not ehminate the total water load within three hours. 



