A sensitive HPLC method for the assessment of metabolic conversion of estrogens

Disorders of estrogen-responsive tissues are frequently associated with aberrations in steroid metabolism due to altered expression of synthesizing and metabolizing enzymes. For instance, overexposure to unopposed 17beta-estradiol has been associated with the pathogenesis of endometrial proliferative disorders, such as endometriosis. Investigations into the metabolic conversion in tissues and cells have been rather limited. This is mostly due to fact that such studies have to make use of radioactive steroid hormones and expensive equipment to obtain sufficient sensitivity. We adapted a sensitive non-radioactive HPLC method to study estrogen metabolism in more detail. This HPLC method is based on the solid phase extraction of estrogens and the derivatization of the steroids with 2-(4-carboxy-phenyl)-5,6-dimethylbenzimidazole. The technique is sensitive, robust and is useful for the detection of aromatase, 17beta-HSD types 1 and 2 and sulfatase activities in lysates of placenta and endometrium.