Competition Between Human Plasma Albumin and Globulins for Estradiol and Sodium Estrone Sulfate

Abstract

Equilibrium ratio determinations of estradiol and sodium estrone sulfate distributed between human red cells and solutions of human plasma albumin, fraction IV-1, or fraction IV-4 of Cohn were made at 38°C and ionic strength of 0.155. The albumin contents of the IV-1 and IV-4 fractions were analyzed by 26% sodium sulfate fractionation. When the influence of the albumin in fractions IV-1 and IV-4 was estimated on the basis of the performance of pure albumin solution, the influence of the globulins was small even on a molar basis. The red cell:albumin ratio, using a physiologic albumin concentration, was nearly the same as the endogenous ratio previously obtained for last trimester human red cells: serum. It is concluded that albumin is responsible for 90% or more of the orientation in human plasma of the estrogens studied.