THE BINDING OF ALDOSTERONE TO PLASMA PROTEINS IN NORMAL, PREGNANT, AND STEROID-TREATED WOMEN*

Abstract
The percentage binding of physiological amounts of 7-H3-aldosterone to undiluted plasma of normal women after dialysis against 5% human serum albumin was 16.4[plus or minus]2.2 (SE). Corresponding values for late pregnancy plasma were 17[plus or minus]1.7 and for women treated with Enovid the percentage binding was 40[plus or minus]5. Results are interpreted as evidence that binding of aldosterone to plasma proteins other than albumin is significant. Any increase of binding during pregnancy is probably small, but treatment with sufficient estrogen can cause increased binding.