• Proceedings of the PSK Conference
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• 2003.04a
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• pp.173.2-174
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• 2003

Many pesticides possess hormonal activity and have been thus classified as endocrine disruptors. Bioallethrin is one of the pyrethroids. synthetic derivatives of naturally occurring pyrethrins. These pyrethroids including bioallethrin have been developed as insectides due to their high insecticidal potency and low mammalian toxicity. Currently, bioallethrin is used to eradicate pests and insects in Korea, providing potential for human exposure. (omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.98-99
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• 2003

Cypermethrin is one of the pyrethroids, synthetic derivatives of naturally occurring pyrethrins. Cypermethrin has been developed as an insecticide, and is now in worldwise use for control of a wide range of insects, providing potential for human exposure. Our previous study suggested estrogenic activity of cypermethrin. A chemical with hormonal activity could adversely affect reproduction and development. (omitted)

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.946-953
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• 2002

Bisphenol A [2, 2 bis (4-hydoxyphenyl) propane; BPA] is a widely used endocrine disruptors and has estrogenic: activities. Although interests on biological effect of BPA are rising, evidences of its effect on immune system are lacking. We investigated that the effect of BPA on immune parameters to postulate the mechanism, and BPA interruptions between neuroendocrine and immune system. BPA was administrated to mice by p.o. (as a drinking water) dose on 0.015, 1.5 and 30 mg/ml for 4 weeks. The BPA treatment did not result in any change in body weight, spleen weight and distribution of lymphocyte subpopulation collected from spleen. BPA induced prolactin production in spleen, and exposure of SPA increased the activity of splenocyte proliferation in response to Con A (p<0.001). The production of a strong Th-1 type cytokine ($IFN-{\gamma}$) was induced while Th-2 type (IL-4) was suppressed by SPA treatment. These were consistent with RT-PCR results of transcription factor GATA-3 and IRF-1. These findings suggested that stimulation of prolactin production by estrogenic effects of SPA would affect cytokine profiles, and lead to imbalanced cellular immune response. In addition, we could speculate that prolactin and cytokine is important mediator involved in network between neuroendocrine and immune system by BPA.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.427-436
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• 2012

Targeted therapy has been a very promising strategy of drug development research. Many molecular mechanims of diseases have been known to be regulated by abundance of proteins, such as receptors and hormones. Chemoprevention for treatment and prevention of diseases are continuously developed. Pre-clinical and clinical studies in chemoprevention field yielded many valuable data in preventing the onset of disease and suppressing the progress of their growth, making chemoprevention a challenging and a very rational strategy in future researches. Natural products being rich of flavonoids are those fruits belong to the genus citrus. Ethanolic extract of Citrus reticulata and Citrus aurantiifolia peels showed anticarcinogenic, antiproliferative, co-chemotherapeutic and estrogenic effects. Several examples of citrus flavonoids that are potential as chemotherapeutic agents are tangeretin, nobiletin, hesperetin, hesperidin, naringenin, and naringin. Those flavonoids have been shown to possess inhibition activity on certain cancer cells' growth through various mechanisms. Moreover, citrus flavonoids also perform promising effect in combination with several chemotherapeutic agents against the growth of cancer cells. Some mechanisms involved in those activities are through cell cycle modulation, antiangiogenic effect, and apoptosis induction.Previous studies showed that tangeretin suppressed the growth of T47D breast cancer cells by inhibiting ERK phosphorylation. While in combination with tamoxifen, doxorubicin, and 5-FU, respectively, it was proven to be synergist on several cancer cells. Hesperidin and naringenin increased cytotoxicitity of doxorubicin on MCF-7 cells and HeLa cells. Besides, citrus flavonoids also performed estrogenic effect in vivo. One example is hesperidin having the ability to decrease the concentration of serum and hepatic lipid and reduce osteoporosis of ovariectomized rats. Those studies showed the great potential of citrus fruits as natural product to be developed as not only the source of co-chemotherapeutic agents, but also phyto-estrogens. Therefore, further study needs to be conducted to explore the potential of citrus fruits in overcoming cancer.

• Journal of Nutrition and Health
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• v.36 no.5
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• pp.452-458
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• 2003

Soybean is a rich source of isoflavones such as genistein and daidzein. Soy isoflavones have both weak estrogenic and anti-estrogenic effects and are structurally similar to tamoxifen, an agent that has an effect similar to that of estrogen in terms of reducing postmenopausal bone loss. The purpose of this study was to determine the effects of differences in protein source (casein vs soy) and isoflavone levels (reduced vs higher levels) on selected bone markers and hormones in growing male rats. Thirty weanling Sprague-Dawley young rats were divided into 3 groups: The control group was fed a casein-based diet, the soy concentrate group was fed soy protein with totally reduced isoflavones content (isoflavones 0.07 mg/g protein), and the soy isolate group was fed soy protein with a higher than normal isoflavones content (isoflavones 3.4 mg/g protein). The degree of bone formation was estimated by measuring serum osteocalcin and alkaline phosphoatase (ALP). By determining collagen cross-linkage by immunoassay and correcting with creatinine values, the bone resorption rate was compared. Serum osteocalcin, growth hormone, estrogen and calcitonin were analyzed using radio immunoassay kits. The bone formation marker and ALP activity were differentiated by protein source, showing higher values than casein in feeding either soy isolate or soy concentrate. In this study using growing rats, the differences in isoflavone contents were not a significant factor in either bone formation or bone reaborption markers. Moreover, the soy isolate group had significantly higher levels of growth hormone than the casein group. The findings of this study suggest that growth hormone is partially responsible for its bone-formation effects in young growing rats. Soy protein and the isoflavones in soy protein are beneficial for bone-formation in growing male rats. Therefore, exposure to soy protein and isoflavones early in life may have long-term health benefits in preventing bone diseases such as osteoporosis. Further study to evaluate the mechanism of action of isoflavones on bones is warranted. (Korean J Nutrition 36(5): 452∼458, 2003)

• Biomolecules & Therapeutics
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• v.8 no.1
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• pp.78-83
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• 2000

The objective of this study was to prevalidate the Organization for Economic Cooperation and Development's (OECD) rodent uterotrophic assay as a test method for screening of potential endocrine disrupting chemicals (EDCs). This study was conducted exactly as described in the OECD protocol documents. A positive control substance, 17$\alpha$-ethinyl estradiol (EE), was administered daily for three days to ovariectomized (OVX) Sprague-Dawley rats at various doses for determine the dose-response curve. Additionally, a pure antiestrogenic chemical, ZM189, 154 was administered to OVX rats at the same time EE to determine the effectiveness of the material against blocking the estrogenic effects of EE. At higher concentration of EE (10 $\mu\textrm{g}$/kg), a statistically significant difference in body weight gain and food consumption was observed compared to vehicle controls. In uterine responses, EE produced a dose-related increase in uterus weights compared to vehicle control. These increases were statistically significant at the >1.0 $\mu\textrm{g}$/kg doses. However, a similar dose-response relationship was not observed in vagina weight. A comparison of the two groups receiving ZM189,154 (0.1 and 1.0 mg/kg) with 0.3 $\mu\textrm{g}$/kg of EE and the group receiving only 0.3 $\mu\textrm{g}$/kg of EE showed dose-related decreases in uterus weights. However, statistical significance was shown in 1.0 mg/kg of ZM189,154. In conclusion, administration of EE produced a dose-related increase in uterine (wet and blotted) weights. Additionally, the 1.0mg/kg dose of ZM189,154 was effective in blocking the estrogenic activity of EE. These data suggest 3-day uterotrophic assay using OVX rats may serve as a good tool for EDCs screening.

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.293-298
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• 2009

Several studies have reported that nonylphenol (NP) and 2,2', 4,6,6'-pentachlorobiphenyl (PCB104) exhibit estrogenic activity. To investigate the estrogenic potency of NP and PCB104 during oocyte maturation, fully vitellogenic oocytes (0.76 mm diameter in average) of yellow fin goby, Acanthogobius flavimanus, were exposed in vitro to these chemicals at different concentrations (0.1, 1, 10, 100, and 1,000 ng/mL) with the exogenous precursor $17\alpha$-hydroxyprogesterone ($17{\alpha}OHP$) 50 ng/mL in the presence or absence of human chorionic gonadotropin (HCG). The production of testosterone (T), estradiol-$17\beta$ (E2), and $17\alpha,20\beta$-dihydroxy-4-pregnen-3-one ($17\alpha20{\beta}OHP$) in response to NP or PCB104 were measured by radioimmunoassay. Steroid levels were also expressed as E2/T and E2/$17\alpha20{\beta}OHP$ ratios. In the absence of HCG, no significant differences in either NP or PCB104 treatment groups were observed. In the presence of HCG, NP treatment did not show significant differences in the production of T, E2, and $17\alpha20{\beta}OHP$ at any concentrations tested, but E2/T ratios were decreased at concentrations of 0.1, 1, 10, and 1,000 ng/mL compared with the control group. PCB104 decreased E2 production at concentrations of 0.1, 10, and 1000 ng/mL, but did not show significant differences in the production of T and $17\alpha20{\beta}OHP$ at any concentration tested. While E2/T ratios were decreased at PCB104 concentrations of 0.1, 1, 10, and 1,000 ng/mL, E2/$17\alpha20{\beta}OHP$ ratios were also decreased at 0.1, 10, and 1,000 ng/mL compared with the control. Results indicate that both NP and PCB104 appeared to have antiestrogenic effects during this phase.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.479-486
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• 2004

Phytoestrogens display estrogen-like activity because of their structural similarity to human estrogens and exhibit high affinity binding for the estrogen receptors (ERs). The prevalence of phytoestrogens in our diets and the biological effects that they may cause need to be fully examined. ER is the ancestral receptor from which all other steroid receptors have evolved. Although phytoestrogens serve specific signaling functions between the plants and insects, fungi, and bacteria, many chemical signals are often misinterpreted as estrogenic signals in non-target organisms such as vertebrates. There are no ERs in plants or in their most common partners, insects. However, Rhizobium soil bacteria have NodD proteins which is an intended target of phytoestrogen signaling and share genetic homology with the ER. These two evolutionarily distant receptors both recognize and respond to a shared group of chemical signals and ligands, including both agonists and antagonists. This review briefly summarizes estrogen and estrogen receptors, kinds of important phytoestrogens, their health effects as well as some of the evolutionary aspects of mechanism by which phytoestrogen mimics the endogenous ER signaling in our body.

• Natural Product Sciences
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• v.6 no.1
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• pp.5-10
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• 2000

The chloroform extract of the seeds of Carica papaya has been screened for the hormonal properties using ovariectomized female rats for estrogenicity, estrogen primed immature rats for progestogenicity and castrated adult male rats for androgenicity. The results revealed that the extract lacks progestogenicity and androgenicity as evident from the failure of the extract treated animals to mimic progestogen and androgen related changes in the target tissues. The increased weight of vagina and uterus, open status of vagina, cornified and epithelial cells in the vaginal smears and hypertrophy in the uterine epithelium, endometrium and stroma with increased glycogen and sialic acid content in the uterus of the chloroform extract treated animals, which are comparable to those of the ovariectomized estrogen treated animals, suggest that the chloroform extract possesses mild estrogenic activity.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.05a
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• pp.127-127
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• 2001

There is a concern that chemicals in our environment are affecting human health by disrupting a normal endocrine function. Much of the concern has focused on chemicals that can interact directly with steroid hormone receptors. The ability of certain man-made chemicals to mimic the effects of natural steroid hormones and their potential to disrupt the delicate balance of the endocrine system in animals are of increasing concern. (omitted)