[Reaction between steroid hormones, the liver and its plasma membrane]

The existence of two systems of steroid (corticosterone, estradiol and testosterone) incorporation into hepatocytes and binding by plasma membranes has been demonstrated. One of the systems is specific (saturated), since it binds and incorporates the hormones only in physiological concentrations. Affinity of this system for corticosterone is much higher than that for estradiol and testosterone. The other system (unsaturated) is nonspecific, since it binds and incorporates all the steroids in high concentrations.