Aromatase inhibitors are endocrine agents with a different mode of action than tamoxifen against breast tumors. In postmenopausal women, estrogen concentrations are maintained primarily via aromatase, a cytochrome P-450 enzyme that acts at the final step in the estrogen synthesis pathway. The first clinically available aromatase inhibitor, aminoglutethimide, was introduced for the second-line t...

In vitro studies show that estrogens acutely modulate synaptic function in both sexes. These acute effects may be mediated in vivo by estrogens synthesized within the brain, which could fluctuate more rapidly than circulating estrogens. For this to be the case, brain regions that respond acutely to estrogens should be capable of synthesizing them. To investigate this question, we used quantitat...

BACKGROUND The optimal ways of using aromatase inhibitors or tamoxifen as endocrine treatment for early breast cancer remains uncertain. METHODS We undertook meta-analyses of individual data on 31,920 postmenopausal women with oestrogen-receptor-positive early breast cancer in the randomised trials of 5 years of aromatase inhibitor versus 5 years of tamoxifen; of 5 years of aromatase inhibito...

The mammalian testis serves two main functions: production of spermatozoa and synthesis of steroids; among them, estrogens are the end products obtained from the irreversible transformation of androgens by aromatase. The aromatase is encoded by a single gene (cyp19) in humans which contains 18 exons, 9 of them being translated. In rat the aromatase activity is mainly located in Sertoli cells of...

Aromatase, a key steroidogenic enzyme that catalyses the conversion of androgens to estrogens, represent a target for endocrine disrupting chemicals. However, little is known about the effect of pollutants on aromatase enzymes in fish. In this study, we first optimized a rainbow trout (Oncorhynchus mykiss) microsomal aromatase assay to measure the effects of 43 substances belonging to diverse c...

Aromatase is a cytochrome P450 enzyme (CYP19) and is the rate limiting enzyme in the conversion of androgens to estrogens. Suppression of in situ estrogen production through aromatase inhibition is the current treatment strategy for hormone-responsive breast cancers. Drugs that inhibit aromatase have been developed and are currently utilized as adjuvant therapy for breast cancer in post-menopau...

Epidemiologic studies have implicated estrogenic exposure as well as human papilloma virus (HPV) infection in cervical carcinogenesis, and some studies have suggested that estrogen and HPV may play synergistic roles in cervical tumorigenesis. In this study, we report a novel finding that approximately 35% of cervical carcinomas tested (n = 19) express aromatase, the enzyme responsible for conve...

Inhibition of aromatase (CYTP450) as a key enzyme in the estrogen biosynthesis could result in regression of estrogen-dependent tumors and even preventing the promotion of breast cancer. Although today potent steroid and non-steroid inhibitors of aromatase are available, isoflavanone derivatives as natural compounds with least side effects have been described as the candidate for a new generati...

n engl j med 360;18 nejm.org april 30, 2009 1912 sions,2 and we also did not detect aromatase protein in the glandular and stromal compartments of ectopic endometrial tissue. We recently found that what was believed to be aromatase protein was mainly endogenous biotin labeling or iron deposits.3 Using three different protocols, we found only barely detectable amounts of aromatase messenger RNA ...

Sex determination in egg-laying amniotes may be fundamentally different from that of placental mammals. The mammalian ovary differentiates normally in the absence of estrogen, whereas estrogen seems to be crucial for proper ovarian development in birds, reptiles, and lower vertebrates. Estrogens are produced normally by the biosynthetic conversion of androgens by the enzyme aromatase (CYP19), w...