ABSTRACT
The regulation of estrogen biosynthesis has attracted scientific and medical interest not only because of its central role in reproduction and potential for therapeutic intervention of estrogen-dependent disease processes, but also because of the unique aspects of the chemical mechanisms involved in the enzymatic aromatization of the steroidal A ring. Increased estrogen biosynthesis by peripheral tissues in postmenopausal women has promoted the development of aromatase inhibitors for treatment of estrogen-dependent breast cancer, since ovarian ablation has had a marginal effect on the reduction of circulating levels of estrogens. In fact, the isotopic kinetic methods proved superior to even the most sensitive estrogen radioimmunoassays in evaluating aromatase inhibitors in the clinical setting. Although different concepts supported their chemical development and biological evaluations, they became the first generation of steroidal and nonsteroidal aromatase inhibitors. The few years of clinical trials will bring to the public new aromatase inhibitors which will provide better therapy for estrogen-dependent breast cancer.
