Local estrogen formation and its regulation in endometriosis

BACKGROUND: It has been well established that endometriosis is an estrogen‐dependent disease. Although the exact pathogenesis of the disease is still unclear, it is known to be characterized by estrogen‐dependent growth and maintenance of the ectopic endometrium and increased local estrogen production. METHODS: The authors reviewed studies on local estrogen production and estrogen activities mediated by estrogen receptors in endometriotic tissues. MAIN FINDINGS: Aberrant expression of several enzymes in local endometriotic lesions contributed to the production and metabolism of estrogens. Aromatase was one of the key therapeutic targets for the regulation of local estrogen formation. Our findings suggest that PGC‐1a, a transcriptional coactivator‐modulating steroid hormone, regulates aromatase expression and activity. Estrogen activities mediated by different types of estrogen receptors abnormally elevated in local tissues could also be involved in the development of endometriosis. The authors demonstrated that the isoflavone aglycone, a partial agonist of the estrogen receptor, suppressed the formation of endometriotic lesions. CONCLUSIONS: Local estrogen production and estrogen activity mediated by estrogen receptors are important potential therapeutic targets for endometriosis.