• Biomedical Science Letters
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• v.25 no.1
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• pp.1-6
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• 2019

The hydroxylation of estradiol results in the formation of catechol estrogens such as 2-hydroxyestradiol ($2-OHE_2$) and 4-hydroxyestradiol ($4-OHE_2$). These catechol estrogens are further oxidized to quinone metabolites by peroxidases or cytochrome P450 (CYP450) enzymes. Catechol estrogens contribute to hormone-induced carcinogenesis by generating DNA adducts or reactive oxygen species (ROS). Interestingly, many of the natural products found in living organisms have been reported to show protective effects against carcinogenesis induced by catechol estrogens. Although some compounds have been reported to increase the activity of catechol estrogens via oxidation to quinone metabolites, many natural products decreased the activity of catechol estrogens by inhibiting DNA adduct formation, ROS production, or oxidative cell damage. Here we focus specifically on the chemopreventive effects of these natural compounds against carcinogenesis induced by catechol estrogens.

• Biomedical Science Letters
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• v.24 no.3
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• pp.143-149
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• 2018

Excessive exposure to estrogens is the most important risk factor for the development of hormone-sensitive cancers, especially breast cancer. Estrogen stimulates the expression of genes and proteins involved in cell proliferation by binding to estrogen receptor (ER). Another possible mechanism of ER-independent carcinogenicity of estrogens is based on the hydroxylation of estradiol resulting in the formation of catechol estrogens. Catechol estrogen 4-hydroxyestradiol ($4-OHE_2$) is further oxidized to catechol estrogen-3,4-quinones, the major carcinogenic metabolites of estrogens. Evidence increasingly supports the critical role of $4-OHE_2$ in hormonal carcinogenesis via DNA adduct formation or production of reactive oxygen species, which finally contribute to the transformation of normal mammary epithelial cells and the enhanced growth of breast cancer cells. It is also reported that the level of $4-OHE_2$ or its quinones is highly up-regulated in urine or tissues of breast cancer patients. Thus, we highlight the oncogenic roles of $4-OHE_2$ in catechol estrogen-induced breast carcinogenesis.

• BMB Reports
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• v.49 no.9
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• pp.488-496
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• 2016

Estrogens are the key hormones regulating the development and function of reproductive organs in all vertebrates. Recent evidence indicates that estrogens play important roles in the immune system, cancer development, and other critical biological processes related to human well-being. Obviously, the gonads (ovary and testis) are the primary sites of estrogen synthesis, but estrogens synthesized in extra- gonadal sites play an equally important role in controlling biological activities. Understanding non-gonadal sites of estrogen synthesis and function is crucial and will lead to therapeutic interventions targeting estrogen signaling in disease prevention and treatment. Developing a rationale targeting strategy remains challenging because knowledge of extra-gonadal biosynthesis of estrogens, and the mechanism by which estrogen activity is exerted, is very limited. In this review, we will summarize recent discoveries of extra-gonadal sites of estrogen biosynthesis and their local functions and discuss the significance of the most recent novel discovery of intestinal estrogen biosynthesis.

• Journal of the Korean Chemical Society
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• v.41 no.4
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• pp.186-197
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• 1997

Estrogens, which play an important role in sex hormone and potential inhibitor of cancer cell proliferation were profiled for normal female and male. The nineteen endogeneous estrogens were simultaneously analyzed by selected ion monitoring method of GC/MS. Urinary estrogens were extracted by using Serdolit AD-2 resin, hydrolyzed with $\beta-glucuronidase/arylsulfatase$ from Helix pomatia, liquid-liquid extraction and quantitatively derivatized by MSTFA/TMSCl mixture in order to be detected on the GC/MS. The good quality-control data were obtained through the precision and accuracy test and the recovery range of them was 80.97∼97.81%. The Korean reference values of urinary estrogens were established and differences were found in normal female compared with normal male.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.182-182
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• 2003

• Development and Reproduction
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• v.9 no.2
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• pp.85-93
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• 2005

Estrogens are known as the steroid hormones and essential regulators of developments, differentiations, and fertility in animals including humans. Recently, classic focus on estrogens which are considered as female hormone is changing in the whole field of reproductive endocrinology. Especially, interest in estrogen functions in male reproduction is increasing more and more, as numerous studies about the endocrine disruptors, interrupting the endocrine system, are being carried out. To understand exactly the function of estrogen in a male reproductive system, a summary for estrogen receptors upon developmental distributions in testis will be useful. In addition to the regulatory roles of estrogen in male, unexpected exposure to exogenous estrogens causes defects of differentiation of male reproductive system and an injury of spermatogenesis. Also, this review highlights the indicator of exogenous estrogens to perturb male fertility. These approaches would give tile practical information about estrogen roles in male development and reproduction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.192-196
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• 2004

The in vitro effect of bisphenol A (BPA) on ovarian steroidogenesis of the longchin goby (Chasmichthys dolichognathus) was investigated. Oocytes taken during the maturing phase (vitellogenic, fully vitellogenic or germinal vesicle breakdown stage) were incubated with BPA (100 ng/mL) in the presence of exogenous precursor $^{3}H-17\alpha\;hydroxyprogesterone\;(^{3}H-17\alphaOHP).$ Steroids were extracted from the media and the isolated oocytes, and the extracts were separated and identified by thin layer chromatography and gas chromatography-mass spectrometry. The identities of the major metabolites were progestogens $[17{\alpha}-hydroxy,20{\alpha}-dihydroprogesterone\;(17{\alpha}20{\alpha}OHP)\;and\;17{\alpha}-hydrxy,20{\beta}-dihydroprogesterone\;(17{\alpha}20{\beta}OHP),$ androgens [androstenedione (A4) and testosterone (T)] and estrogens [estrone $(E_1)\;and\;estradiol-17{\beta}(E_2)].$ BPA treatment inhibited production of estrogens in all the maturing phases and progestogens in the germinal vesicle migrating stage. Percentage yield of estrogens was decreased with increased yield of androgens. In conclusion, BPA had an inhibitory effect on the conversion of $^3H-17\alphaOHP$ to estrogens and progestogens. These results demonstrate that BPA can act either estrogenic or anti-estrogenic effects.

• Korean Journal of Veterinary Research
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• v.13 no.1
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• pp.23-30
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• 1973

Thin layer, paper and column chromatography were compared for the separation, detection and quantitation of three kinds of estrogen in urine of dairy cows. While thin layer chromatography utilizing silica gel was better for the detection of estrogens, column chromatography using celite 545 was preferable. Spectrophotometry was compared with fluorometry for determination of estrone, estradiol-17 ${\beta}$ and estriol eluted by paper chromatography and column chromatography. Optical density of three standard estrogens showed almost same curve at maximum absorption wave length of 230 and $282m{\mu}$. However, the former showed a higher peak. In fluorometry, the fluorescence intensity of estrone and estradiol-17 ${\beta}$ were rather strong, when the estrogens were dissolved in sulfuric acid, and showed higher sensitivity than that of the spectrophotometry. However, in the case of estriol was exceptional.

• 대한생식의학회:학술대회논문집
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• 2004.11a
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• pp.28-29
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• 2004

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.05a
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• pp.125-125
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• 2001

It has been hypothesized that environmental estrogens may play roles in the increasing incidence of breast and testicular cancers and another problems of the reproductive systems. Alkylphenols which are widely used as plastic additives and surfactants have been shown to induce estrogenic responses. The E-screen assay was developed to assess the estrogenedity of environmental chemicals using the profiferation effect of estrogens on their target cells as an end point. (omitted)