Estrogenic metabolites of circulating androgens have important effects on the organization and activation of neural circuits controlling reproductive behavior and physiology in males of many vertebrate species. Previous studies indicate that aromatase, the enzyme that converts androgens to estrogens, is expressed most abundantly in neurons in limbic brain regions. Songbirds are unique in that a...

Estrogens are essential for bone mass accrual but their role before sexual maturation has remained elusive. Using in situ hybridization and immunohistochemistry, we investigated the expression of both estrogen receptor (ER) alpha and beta mRNA and protein as well as several mRNAs coding for enzymes involved in sex steroid metabolism (aromatase, type I and II 17 beta-hydroxysteroid dehydrogenase...

Aromatase is the cytochrome P450 enzyme that cleaves the C10-C19 carbon-carbon bond of androgens to form estrogens, in a three-step process. Compound I (FeO(3+)) and ferric peroxide (FeO2(-)) have both been proposed in the literature as the active iron species in the third step, yielding an estrogen and formic acid. Incubation of purified aromatase with its 19-deutero-19-oxo androgen substrate ...

Polybrominated diphenyl ethers (PBDEs) are additive flame retardants that have been found in the environment as well as human tissues. Environmental concentrations of these compounds have been increasing in many parts of the world in recent years. Due to their structural similarity, PBDEs are believed to have similar toxicity to PCBs, but their toxicological properties are still being determine...

Lung cancer is the most common cancer in the world. It is a highly lethal disease in women and men, and new treatments are urgently needed. Previous studies implicated a role of estrogens and estrogen receptors in lung cancer progression, and this steroidal growth-stimulatory pathway may be promoted by tumor expression and activity of aromatase, an estrogen synthase. We found expression of arom...

The vertebrate brain is a source of estrogen (E) via the expression of aromatase (E-synthase). In the zebra finch (Taeniopygia guttata), despite documented dimorphisms in E-action, no differences are detectable in circulating E, or the neural levels of aromatase transcription, activity, or somal protein expression. Studies of aromatase expression at the light- and electron-microscope levels rev...

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...

PATIENT Female, 56 FINAL DIAGNOSIS: Breast cancer Symptoms: Solid mass in the right breast Medication: Exemestane Clinical Procedure: - Specialty: Oncology. OBJECTIVE Unusual clinical course. BACKGROUND The efficacy of third-generation aromatase inhibitors for hormone receptor-positive postmenopausal metastatic breast cancer is well established. Although several clinical trials have reporte...

Spontaneous canine mammary inflammatory carcinoma (IMC) shares epidemiologic, histopathologic and clinical characteristics with the inflammatory breast carcinoma (IBC) disease in humans. We have analysed the steroids levels in serum and in tissue homogenates of IMC, the expression of two of their receptors (androgen and beta-estrogen) and of three enzymes included in the steroidogenesis pathway...

Steroid 5AR converts testosterone to dihydrotestosterone; steroid aromatase converts testosterone to oestradiol in males and females (androgen deprivation results in oestrogen deprivation). Oestradiol, the product of testosterone aromatization, binds to the androgen and oestrogen receptors. Dihydrotestosterone (DHT) mediates cellular apoptosis through the paracrine prostate stromal cell factors...