[Aromatase inhibitors: pharmacological aspects].

Selective new aromatase inhibitors are a new class of agents that are of considerable interest in the treatment of hormone-dependent breast cancer in postmenopausal women. Aromatase is an enzymic complex that catalyses the conversion of the adrenal androgens androstenedione and testosterone to estrone. In postmenopausal women, the process of peripheral aromatisation accounts for the majority of circulating estrogens. The selective inhibition of estrogen production by aromatase inhibitors is an efficient strategy for breast cancer treatment. These compounds are classified as irreversible inhibitors of aromatase (type I), and comprise steroidal compounds. Reversible inhibitors of aromatase, which comprises non-steroidal compounds are type II aromatase inhibitors. Second and third generation aromatase inhibitors are considerably more potent and more specific in their ability to inhibit aromatase, as compared with first generation compounds (aminoglutethimide).