Effect of Ethinyl Estradiol (Estinyl) on Plasma Renin Activity

In the process of establishing the normal values for plasma renin activity in our laboratory we found that the plasma renin activity in one normal woman was much greater than that of 12 other normal subjects, both under basal recumbent conditions and in response to sodium restriction and the stress of standing upright for four hours. In searching for the cause of this, it was considered that the elevated values in this woman were possibly due to the oral contraceptive medication that she was taking. To study this further a group of seven control subjects were given ethinyl estradiol (E.E.)1 for three weeks and its effect on the plasma renin activity and aldosterone2 excretion rate was measured.