• Biomedical Science Letters
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• v.11 no.3
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• pp.333-336
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• 2005

Environmental endocrine disruptors are very toxic to the animals including humans. They are hormone-like acting chemicals which can be found in our normal daily life. We have examined the toxic effect of bisphenol A and if lactic acid bacteria could suppress this toxic effect. Thirty rats were divided into three groups (control, bisphenol A treated, bisphenol A and lactic acid bacteria treated). Treatments were carried out at an interval of 12 hours for each group. Control group showed normal and clear morphology of tissues. Cells were fine in their shape and color, and density was high enough for the normal function. However, bisphenol A treated group was abnormally destructed in cell morphology. In the testis, sperms were totally destructed. When treated with lactic acid bacteria together, the toxic effect of bisphenol A was clearly decreased. This study indicated that bisphenol A was toxic in any concentration especially for the liver and testis, however, lactic acid bacteria could suppress the toxic effects of bisphenol A.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.181-181
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• 2001

1,2-Dibromo-3-chloropropane (DBCP), a soil fumigant against nematodes, is a genotoxic carcinogen and also is classified by World Wildlife Fund as endocrine disruptors. DBCP has been extensively studied on genotoxicity, carcinogenicity, and damage in male reproductive-related organs. However, information on precise mechanism of mutagenesis and carcinogenesis of DBCP is yet unknown. Thus the mutation spectrum and mechanism of DBCP was determined in lacI transgenic Big Blu $e^{R}$ Rat2 fibroblast cell lines.(omitted)d)

• Development and Reproduction
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• v.18 no.4
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• pp.187-195
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• 2014

Polycyclic aromatic hydrocarbons (PAHs), which are ubiquitous in the air, are present as volatile and particulate pollutants that result from incomplete combustion. Most PAHs have toxic, mutagenic, and/or carcinogenic properties. Among PAHs, benzo[a]pyrene (B[a]P) and dimethylbenz[a]anthracene (DMBA) are suspected endocrine disruptors. The testis is an important target for PAHs, yet effects on steroidogenesis in Leydig cells are yet to be ascertained. Particularly, disruption of testosterone production by these chemicals can result in serious defects in male reproduction. Exposure to B[a]P reduced serum and intratesticular fluid testosterone levels in rats. Of note, the testosterone level reductions were accompanied by decreased steroidogenic acute regulatory protein (StAR) and $3{\beta}$-hydroxysteroid dehydrogenase isomerase ($3{\beta}$-HSD) expression in Leydig cells. B[a]P exposure can decrease epididymal sperm quality, possibly by disturbing the testosterone level. StAR may be a key steroidogenic protein that is targeted by B[a]P or other PAHs.

• Environmental Mutagens and Carcinogens
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• v.26 no.2
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• pp.53-58
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• 2006

Normally, environmental toxicants are classified as endocrine disruptors if they interfere with regulation of cellular function by endogeneous steroids through inhibition of receptor binding and/or transcriptional activation. So, many studies have been performed about agonist/antagonist of hormone receptor to study mechanisms of endocrine disruptors. If toxicants affect steroid biosynthesis and/or degradation and alter hormone homeostasis, these also are classified as endocrine disruptors. But there are not many studies of the mechanisms of endocrine disruptors on the basis of alteration of steroid biosynthesis and/or degradation. Isolation and culture of Leydig cells from testis is one of methods for the steroidogenesis screening assays to evaluate a substance for altering steroidogenesis. Leydig cells were harvested using the method described by Klinefelter with modifications. Leydig cells were purified by perfusion of testis and incubation ($34^{\circ}C$, 80cycles/minute, 20 minutes) with collagenase (0.25 mg/kg), centrifugal elutriation, percoll gradient centrifugation and BSA multidensity gradient centrifugation. To confirm if this method is one of appropriate tools to evaluate a substance for altering steroidogenesis, ketoconazole, positive control was administered to purified Leydig cells. Ketoconazole ($10^{-8}M$ and above) significantly reduced testosterone production in purified Leydig cells. From above results, we suggest that this method for steroidogenesis screening assay appears to be a appropriate tool to detect suspected compounds for altering steroidogenesis.

• Development and Reproduction
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• v.6 no.1
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• pp.25-30
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• 2002

Endocrine disruptors have been reported to adversely affect reproduction and embryonic development in wild animals. One of the major abnormalities observed during early embryonic development is cellular fragmentation. In this study, we exposed mouse preimplantation embryos to PCB, BPA and DDT in vivo or in vitro. Embryos exposed to endocrine disrupter showed a variety of morphological abnormalities such as fragmentation, irregular blastomeres and cracked empty zonae pellucidae. To investigate the levels of gene expression related which genes contribute to apoptosis in preimplantation mouse embryos, we carried out the reverse transcription polymerase chain reaction to assess mRNA levels far apoptotic gene. Bcl-2, bad and bax expression levels were compared between control group and endocrine disrupter treated group. Expression level of bcl-2 gene tended to be lower in the treated group than control while expression levels of bad and bax genes were higher in the treated group. Results of this study may provide a useful tool for rapidly screening developmental toxicants in preimplantation embryos exposed to endocrine disruptors in vivo or in vitro.

• Biomolecules & Therapeutics
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• v.8 no.2
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• pp.147-152
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• 2000

The rodent uterotrophic assay is currently recommended as one of the primary in vivo assays far endocrine disrupting chemicals by the Organization for Economic Cooperation and Development (OECD) and Endocrine Disruptor Screening and Testing Advisory Committee (US EPA EDSTAC). Generally, this assay relies on the rapid increase in uterus and vagina weights when exposed to estrogenic compounds. Phthalate esters have been used extensively as a plasticizer in the manufacture of plastic products such as PVC films and medical devices. Recently, phthalate esters have been shown to induce endocrine system mediated responses. However, a flew studies have been conducted for the screening of their estrogenic activity. In this study the estrogenic activity of seven phthalate esters, butyl benzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), di-n-butylphthalate (DBP), diethylphthalate (DEP), di-n-pentylphthalate (DPF), di-n-propylphthalate (DPrP) and dicyclohexylphthalate (DCHP), was examined in uterotrophic assay. Phthalate esters dissolved in corn oil were administered to ovariectomized (OVX) female Sprague-Dawley rats by sub-cutaneous injection for three consecutive days. fiats were sacrificed 24h after final treatment, and then uterus and vagina weights were deter mined. All phthalate esters tested in this assay did not change talc uterus and vagina weights at dosage levels up to 200 mg/kg/day treatment. These results demonstrated that phthalate esters did not exhibit estrogenic activity in vivo uterotrophic assay.

• Journal of Integrative Natural Science
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• v.5 no.2
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• pp.79-83
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• 2012

Trialkyltin n-$Bu_3SnH$, an endocrine disruptor, was slowly converted by the catalytic action of group 4 $Cp_2MCl_2$/Red-Al (M = Ti, Zr, Hf) to produce two phases of products: one is an insoluble cross-linked solid, polystannane in 7-23% yield as minor product via redistribution/dehydrocoupling combination process, and the other is an oil, hexabutyldistannane in 69-90% yield as major product via simple dehydrocoupling process. Redistribution/dehydrocoupling process first produced a low-molecular-weight oligostannane possessing partial backbone Sn-H bonds which then underwent an extensive cross-linking reaction of backbone Sn-H bonds, leading to an insoluble polystannane. This is the first exciting example of redistribution/dehydrocoupling of a tertiary hydrostannane catalyzed by early transition metallocenes.

• Toxicological Research
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• v.27 no.1
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• pp.49-52
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• 2011

The aim of this study is to investigate how many leiomyoma patients are exposed to bisphenol-A (BPA), an endocrine disruptor, and whether the serum concentration of BPA is related to leiomyoma growth. Initially, 128 patients were divided into one control and three leiomyoma groups (mild, moderate and severe) according to the size of the leiomyomas. Serum BPA concentrations were measured by liquid chromatography and mass spectrometry (LC/MS). Nearly two-thirds of leiomyoma patients were exposed to BPA and the range of BPA was from non-detection to 2.603 ng/ml. The mean BPA concentrations in the groups were $1.015{\pm}0.775\;ng/ml$ (control), $0.774{\pm}0.834\;ng/ml$ (mild), $1.261{\pm}0.797\;ng/ml$ (moderate) and $1.244{\pm}0.860\;ng/ml$ (severe) (p = 0.158). After recombination into two group, Group 1 (control plus mild) vs. Group 2 (moderate plus severe), higher level was found in Group 2 even with no statistical significance (p = 0.06). In conclusion, about two-thirds of leiomyoma patients were exposed to BPA, but it may not have growth promoting effect on leiomyoma.

• Journal of Environmental Science International
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• v.15 no.8
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• pp.811-817
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• 2006

We were carried out to monitor pesticide residues in herbal medicine. In Korea Pharmacy, these are no critics for pesticides except 5 kinds of organic chlorines (BHC, DDT, Aldrin, Endrin, Dieldrin) and heavy metals. We analysed 53 kinds of pesticides consisted of 14 kinds of organochlorines, 20 kinds of organophosphoruses, and 19 kinds of pesticides estimated endocrine disruptor on 373 samples consisted with 30kinds of herbal medicine. In this study, Domestic, Chinese and Japanese herbal medicines were tested with GC/ECD, GC/NPD and then confirmed with GC/MSD. Recoveries were 75$\sim$l10% in ECD detector and 76$\sim$97% in NPD detector. Detection limits were 0.004$\sim$0.064ppm in ECD detector and 0.006$\sim$0.094ppm in NPD detector. Organochlorines and others were not detected in samples.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.342-350
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• 2008

This study was carried out to investigate the suitability of the pubertal assay and the enhanced TG 407 as methods for detection of endocrine-mediated effects. Thyroid function was also considered. Male and female Sprague-Dawley rats were gavaged daily with 0, 25, 50, 100 mg/kg metribuzin in corn oil during 30 days. The effects of metribuzin on thyroid gland, the genital organs and thyroid hormone were measured in male and female rats. Dose of metribuzin 50 mg/kg/day increased relative weight of testis, prostate, and seminal vesicle in male rats but relative weight of thyroid gland was not significantly different from control group. Dose of metribuzin 25 mg/kg/day decreased relative weight of thyroid gland in female rats. Another purpose of this study was to investigate the effects of endocrine-disruptors as like thyroid hormone in vitro. Luciferase activity was measured to detect reaction of test chemicals and thyroid hormone response elements in HeLaTRE cell. Dose of metribuzin from 1 to 1,000 nM increased to 106-122% of luciferase activity.