Metabolism of catechol estrogen by human erythrocytes

In a study designed to evaluate the kinetics of catechol estrogen formation from plasma estrone in vivo, we obtained evidence that the red blood cell (RBC) enzyme, catechol-O-methyl transferase, catalyzes the transformation of 2-hydroxyestrone to 2-methoxyestrone. Under in vitro conditions, the rate of conversion of 2-hydroxyestrone to 2-methoxyestrone by human RBC's was such that 7 nmol of 2-methoxyestrone were formed per h per ml of RBC.