Abstract

Certain steroids can react with proteins to form stable, covalent addition products. 16α‐hydroxyestrone and the glucocorticoids, for example, contain ketol moieties which permit them to react non‐enzymatically with proteins by forming Schiffbase rearrangement products with lysine residues. The oral contraceptive agent, 17α‐ethinylestradiol, can add to proteins after being enzymatically activated by microsomal oxidation. Elevated plasma levels of these steroids result in an increased amount of protein modification in vivo. Recent investigations have linked the occurrence of steroid‐modified proteins with pathological sequelae associated with high steroid levels.