Distribution of Steroid Hormones in Biologic Systems

Abstract

The distr. coeff. for estriol between rabbit serum and red cells approaches that found for the endogenous estrogen content of mammalian blood. No demonstrable amt. of estrone palmitate penetrated the red cell from a serum dispersion. Na estrone sulfate penetrated the red cell, the distr. coeff.,red cells: saline, being approx. 2. The distr. coeff. for estradiol between red cells and serum approx. 0.2 over a 270-fold range of concn., whether in vivo or in vitro. The detn. of estradiol content in blood and tissues after an intraven. injn. showed that muscle cells were readily permeable and took up 2.5 times as much estradiol as adipose tissue, indicating impermeability of the fat cell wall.