Effect of Adrenal Steroids on Body Electrolytes 183 



Aldosterone prevents sodium excretion in a very marked 

 manner in about the same intensity and for about the same 

 duration (five to seven hours) in all age groups (Fig. 2). 



The only difference to be noted is that in old animals the 

 onset of the sodium-retaining effect of the steroid is retarded, 



% 

 zzo 



zoo 



ISO 



m 



140 

 120 

 100 

 80 

 60 

 40 

 20 



IZ'i456789t 



Fig. 2. Urinary sodium and potassium excretion of adrenal- 



e<*I;omized male rats of different age groups treated ^^^th aldosterone 



(0 010 mg./kg.). 



Thick line : sodium excretion. 

 Thin line : potassium excretion. 

 Other figures as for Fig. 1. 



the maximal effect falUng in the collecting period of the third 

 hour, instead of in the preceding period. 



The effects of aldosterone on potassium excretion depend 

 upon the age groups in question. 



In young animals, aldosterone does not affect potassium 

 excretion until the fourth collecting hour. From the fifth 



