86 



G. I. M. SWYER 



patient A.E.L. If anything, the ratio is higher in the second 

 half of the cycle — i.e. sodium retention is less premenstrually. 

 In Fig. Sa, the urinary Na/K ratio appears to rise sharply just 

 at the time of ovulation — i.e. at the time of an oestrogen 

 peak, when, according to the usual view, the tendency should 

 be towards sodium retention. 



m.Eq./l. -6 



10 



20 



25 



HB CYCLE DAYS 



Fig. 5. Salivary sodium and potassium concentrations and ratios 

 in a woman who experienced premenstrual tension. 



Figs. 4-6 relate to women who experienced definite pre- 

 menstrual tension. In Fig. 4 the salivary and urinary Na/K 

 ratios are compared. The latter (note that its scale is ten 

 times that of the salivary Na/K ratio) is much more variable 

 than the former, and neither shows any definite pattern. 

 Certainly there is no evidence of sodium retention premen- 

 strually. Fig. 5 shows the salivary Na/K ratios in another 



