Effect of Adrenal Steroids on Body Electrolytes 181 



own adrenals, as well as to avoid strain-bound differences in 

 sensitivity. 



To test the action of steroids on urinary and electrolyte 

 excretion, we have used the method described in detail by 

 Desaulles and Meier (1956), the only difference being that, 

 instead of collecting urine from the fifth to seventh hour after 

 treatment and loading, we collected it in different groups from 

 the 30th minute to the second hour and a half, from the 

 first to the third hour, from the second to the fourth hour, 

 and from the seventh to the ninth hour following treatment, 

 this procedure enabling us to follow closely the excretion of 

 urine and of electrolytes. Both male and female animals 

 were used, the age groups being: 



(a) animals about five weeks old and about 50 g. in weight, 



(b) animals about 15 weeks old and about 150-180 g. in 

 weight, 



(c) animals about one year old and exceeding 300 g. in 

 weight. 



All animals used in these experiments were kept isolated in 

 metal cages at constant temperature (26°) and relative humid- 

 ity (75 per cent), the number of animals per group varying 

 from six to 12. The animals were given full standard rat cake 

 (Nafag A.-G., St. Gallen) and water ad libitum until the 

 beginning of the experiment. 



The steroids chosen, aldosterone and Cortisol, are known to 

 be secreted by the rat adrenals (Bush, 1953; Singer, 1957). 

 Cortisol was used as free alcohol, aldosterone was used as 

 DL-aldosterone acetate, the activity of which is just one half of 

 D-aldosterone (Schmidlin et al., 1955, 1957). All substances 

 were dissolved in sesame oil and injected intramuscularly. 



The doses used in these experiments were chosen from 

 previous experiments (Desaulles and Meier, 1954; Desaulles, 

 1958) and lay within a dose range corresponding to sub- 

 maximal effects. For aldosterone acetate 0-01 mg./kg. was 

 given, and for Cortisol 5 mg./kg. 



As the excretion of urine and urinary electrolytes differs 



