188 



P. A. Desaulles 



1954; Desaulles, 1958) and which is followed by enhanced 

 sodium excretion (Fig. 8). In males these effects tend to dis- 

 appear with advancing age. 



On potassium, one observes the characteristic excretory 

 response whose intensity is particularly high in young animals, 

 its onset being somewhat more rapid in adult and old animals. 



% 



160 

 140 

 120 

 100 

 00 

 60 

 JO 



eo 



+ jO^ 



I Z ? 4 f ^ f S 9 t 



Fig. 7. Urinary excretion of adrenalectomized male rats of dif- 

 ferent age groups treated with Cortisol (5 mg./kg.). 

 Abscissa : Duration of experiment (hours) ; collecting period 2 hours. 

 Ordinate : Urinary excretion as a percentage of the values of control 



animals. 



Continuous line : 5-week-old rats. 

 Interrupted line: 15-week-old rats. 

 Dotted line : one-year- and more-old rats. 



The effect of Cortisol on the sodium/potassium ratio is first 

 to lower it moderately in males, and to raise it afterwards to 

 high positive values (Fig. 9). This effect, most marked in 

 young animals, declines with increasing age. 



In female rats, Cortisol has a stronger enhancing effect on 

 urinary output than in males (Fig. 10). With age, this effect 

 increases and a certain latency of onset seems apparent. 



