• Toxicological Research
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• 제22권1호
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• pp.15-22
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• 2006

Many of endocrine disrupting chemicals induce effects via interaction with hormone receptors and responsive elements in target cells. We investigated endocrine disrupting effects of some food additives and contaminants including BHA, BHT, ethoxyquin, propionic acid, sorbic acid, benzoic acid, CPM, aflatoxin B1, cadmium chloride, genistein, TCDD and PCBs in yeast transformants expressing human steroid hormone receptors along with steroid responsive elements. The response limit of genetically recombinant yeast to $17{\beta}$-estradiol, testosterone and progesterone was $1{\times}10^{-16},\;1{\times}10^{-12}\;and\;1{\times}10^{-13}M$, respectively. BHT induced weak transcriptional activity in estrogen sensitive yeast, while BHA and sorbic acid interacted weakly with androgen receptor/responsive element. CPM induced transcriptional activities in all types of yeasts sensitive to steroid hormones. Zearalenone and genistein induced high transcriptional activation in estrogen sensitive yeast with relative potencies almost $10^8$ folds lower than $17{\beta}$-estradiol. TCDD induced transcriptional activation weakly in estrogen- and progesterone- sensitive yeasts. This study elucidated that recombinant yeast is a sensitive and high-throughput system and can be used for the direct assessment on chemical interactions with steroid receptors and responsive elements. Also, the present study raises the requirement of evaluation on the endocrine disrupting effects of BHT, BHA, sorbic acid, CPM and TCDD for their transcription activity in yeast screening system though weak in intensity.

• The Korean Journal of Physiology and Pharmacology
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• 제3권2호
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• pp.215-222
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• 1999

Nonylphenol (NP) is a widespread environmental pollutant that has been shown to exert both toxic and estrogenic effects on mammalian cells. As the effects of NP on the reproductive system of adult male vertebrates are virtually unknown, we investigated not only the changes of reproductive hormone secretion in serum after chronic exposure to NP but also, in order to identify the site of its action, the reproductive hormone secretion in serum 48 hours after microinfusion of NP within hypothalamic preoptic area (POA). In the chronic exposure, the luteinizing hormone (LH), follicle stimulating hormone (FSH), and testosterone in serum were decreased but prolactin (PRL) concentrations were increased. The LH, FSH, and testosterone in serum were decreased through the direct infusion of NP into POA, while there was no difference in mean serum prolactin between NP and control groups. These observations suggest that NP as endocrine disruptor has modulatory effects on hypothalamo-pituitary-gonadal axis and that the site of action of NP could be hypothalamic POA.

• 한국독성학회:학술대회논문집
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• 한국독성학회 1997년도 국제심포지움 및 추계학술대회
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• pp.32-37
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• 1997

• Journal of Preventive Medicine and Public Health
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• 제54권1호
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• pp.37-45
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• 2021

Objectives: Bisphenol A (BPA) is used in the electrical, mechanical, medical, and food industries. Previous studies have suggested that BPA is an endocrine disruptor. Regulation of BPA has led to increased use of bisphenol F (BPF) and bisphenol S (BPS). However, few studies have investigated the associations of BPF and BPS with thyroid dysfunction in children. Our study investigated the associations of prenatal BPA and early childhood BPA, BPF, and BPS exposure with thyroid function in 6-year-old children. Methods: Prenatal BPA concentrations were measured during the second trimester of pregnancy in an established prospective birth cohort. We measured urinary BPA, BPF, and BPS concentrations and thyroid hormone levels (thyroid-stimulating hormone, total T3, and free T4) in 6-year-old children (n=574). We examined the associations between urinary bisphenol concentrations and percentage change of thyroid hormone concentrations using multivariate linear regression. We also compared thyroid hormone levels by dividing the cohort according to BPA, BPF, and BPS concentrations. Results: The associations between prenatal BPA and total T3 levels were statistically significant in all models, except for girls when using a crude model. The associations between urinary BPA and BPS concentrations and levels of all thyroid hormones were not statistically significant. However, we observed that lower free T4 levels (-1.94%; 95% confidence interval, -3.82 to -0.03) were associated with higher urinary BPF concentrations in girls only. Conclusions: Our findings identified significant associations between prenatal BPA exposure and total T3 levels in all children and between BPF exposure and free T4 levels in girls only.

• 한국수산과학회지
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• 제56권3호
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• pp.309-314
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• 2023

Shark populations are constantly decreasing owing to environmental destruction and overfishing; thus, sharks are now at risk of extinction, with 30.5% of species classified as endangered on the International Union for Conservation of Nature's Red List. Sharks are apex predators and keystone species in balancing the marine food chain; their extinction would create an imbalance in the entire marine ecosystem. Assisted reproductive technology is a last resort for protecting animals facing extinction. Here, as a proactive effort toward building a hormone-induced artificial insemination protocol for endangered wild sharks, we identified the possibility of germ cell maturation by administration of GnRH, a commercially produced synthetic salmon gonadotropin-releasing hormone, and calculated its optimum dosage and injection timing. The experiment was conducted on one shark species, Chiloscyllium plagiosum. Injections were administered in 24 h intervals to C. plagiosum females, and 0.2 mL/kg+0.2 mL/kg were the optimal doses. These doses effectively induced maturation and, and ovulation, and oocyte release. Our results confirm that GnRH is a suitable tool for shark hormone-induced artificial insemination and indicate that this method may facilitate the conservation of endangered shark species.

• 한국동물학회지
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• 제39권4호
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• pp.337-351
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• 1996

멜라토닌은 대뇌와 소뇌 사이에 위치한 송과선에서 분비되는 호르몬으로 빛이 없는 밤에만 분비된다. 멜라토닌은 분자적 수준에서부터 개체의 행동에 이르기 까지 다양한 기능을 보인다. 특히, 생식에 미치는 영향은 광범위하여, 온대지방에 사는 대부분의 동물은 주위 환경에 적응하여 종족을 유지하는 유일한 계절적 번식을 한다. 햄스터의 생식활동은 여름에 왕성하고 겨울에 정지된다.이는 많은 환경요소중 광주기의 효과가 송과선에 의해 제거하면 광주기의 영향은 사라진다. 즉 생식에 미치는 광주기의 효과가 송과선에 의해 중재 됨을 의미한다. 또한 송과선 호르몬인 멜라토닌의 적절한 처리는 생식활동을 억제한다. 따라서 멜라토닌은 생식에 미치는 광주기의 정보를 생식내분비계로 전달하는 신경전달물질로 사료된다. 시상하부의 특정부위를 절제한 후 광주기나 멜라토닌을 처리하여 멜라토닌의 작용부위에 관한 연구가 되었으나 동물마다 차이점을 보인다. 대부부의 동물에서 공통적인 부위는 suprachiasmatic nuclei와 pars tuberalis이다. 멜라토닌이 생식에 미치는 작용기작은 아직 밝혀지지 않았다. 이는 멜라토닌의 지속적 처리가 멜라토닌의 장기적처리는 이들 호르몬의 분비를 저하시키고, 시상하부에서의 gonadotropin-releasing hormone (GnRH)양을 증가시킨다. 이 결과는 멜라토닌의 지속적인 처리가 시상하부로부터의 GnRH 양을 분비를 감소킴으로써 생식활동을 억제하는 것으로 사료된다.그러나, 멜라토닌에서 GnRH 신경까지의 정보전달은 아직 밝혀지지 않았다. Opioid 신경에 대한 광주기와 멜라토닌의 효과가 동일한 점은 opioid신경의 매개체 역할을 제시하고 있다. 최근에 멜라토닌 수용체가 개구리의 피부와 몇몇 동물의 뇌와 시세포에서 크로닝되었다. 이수용체는 G protein과 관련되고 cAMP 생성을 억제한다. 앞으로 이 멜라토닌 수용체의 존재여부와 분자생물학적 연구는 멜라토닌의 작용부위와 표적세포에서의 작용기작을 설명하는 데 크게 기여할 것으로 기대된다.

• Toxicological Research
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• 제16권1호
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• pp.27-31
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• 2000

Recently, there is a worldwide concern that a great number of man-made chemicals have a hormone-like action both in humans and in animals. EPA and OECD are developing screening programs using validated test systems to determine whether certain substances may have an effect on humans. In the present study, the establishment of in vivo short-term test system for pubertal female assay with thyroid to detect endocrine disrupting chemicals was tried using a model substance, methoxychlor (MC), a chlorinated hydrocarbon insencticide. Forty female rats were assigned to four groups. MC was administered at dose levels of 0, 8, 40 and 200mg/kg by gavage to female rats from day 21 post partum to the completion of vaginal opening. We evaluated body weight change, age at vaginal opening, onset of estrous cyclicity, age at first esturs, ovary weight, and serum concentrations of thyroxine and thyroid stimulating hormone in female rats. The age at vaginal opening of females receiving 40 200mg/kg was significantly younger than control. The onset of estrus cyclicity and age at first estrus of females receiving 200mg/kg was also younger than controls. There was no effect of treatment on body weight, ovary weight, and hormone concentration. Based on these results, it can be concluded that application of MC at dose level of 40mg/kg affects the vaginal opening and application of MC at dose level of 200mg/kg accelerates the vaginal opening and the onset of estrus cylicity.

• Clinical and Experimental Reproductive Medicine
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• 제46권2호
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• pp.50-59
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• 2019

Anti-$M{\ddot{u}}llerian$ hormone (AMH), a peptide growth factor of the transforming growth $factor-{\beta}$ family, is a reliable marker of ovarian reserve. Regarding assisted reproductive technology, AMH has been efficiently used as a marker to predict ovarian response to stimulation. The clinical use of AMH has recently been extended and emphasized. The uses of AMH as a predictive marker of menopause onset, diagnostic tool for polycystic ovary syndrome, and assessment of ovarian function before and after gynecologic surgeries or gonadotoxic agents such as chemotherapy have been investigated. Serum AMH levels can also be affected by environmental and genetic factors; thus, the effects of factors that may alter AMH test results should be considered. This review summarizes the findings of recent studies focusing on the clinical application of AMH and factors that influence the AMH level and opinions on the use of the AMH level to assess the probability of conception before reproductive life planning as a "fertility test."

• 한국환경성돌연변이발암원학회지
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• 제22권3호
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• pp.175-182
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• 2002

Endocrine disruptors (EDs) are the chemicals that affect endocrine systems through activation or inhibition of steroid hormone response. It is necessary to have a good system to evaluate rapidly and accurately endocrine-disrupting activities of suspected chemicals and their degradation products. The key targets of EDs are nuclear hormone receptors, which bind to steroid hormones and regulate their gene transcription. We constructed a co-expression system of Gal4p DNA binding domain (DBD)- ligand binding domain of human estrogen receptor $\alpha$ or $\beta$, and Gal4p transactivation domain (TAD)-co-activator AIB-1, SRC-1 or TIF-2 in Saccharomyces cerevisiae with a chromosome-integrated lacZ reporter gene under the control of CYC1 promoter and Gal4p binding site (GAL4 upstream activating sequence, GAL4$_{UAS}$). Expression of this reporter gene was dependent on the presence of estrogen or EDs in the culture medium. We found that the two-hybrid system with combination of the hER$\beta$ LBD and co-activator SRC-1 was most effective in the xenoestrogen-dependent induction of reporter activity. The extent of transcriptional activation by those chemicals correlated with their estrogenic activities measured by other assay systems, indicating that this assay system is efficient and reliable for measuring estrogenic activity. The data in this research demonstrated that the yeast detection system using steroid hormone receptor and co-activator is a useful tool for identifying chemicals that interact with steroid receptors.s.

• Journal of Plant Biotechnology
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• 제42권3호
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• pp.168-179
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• 2015

We previously identified the rice gene, OsSAP, as an encoder of a highly conserved putative senescence-associated protein that was shown to have anti-apoptotic activity. To confirm the role of OsSAP in inducing abiotic stress tolerance in rice, we introduced OsSAP and AtBI-1, a plant homologue of Bax inhibitor-1, under the control of the CaMV 35S promoter into the rice genome through Agrobacterium-mediated transformation. The OsSAP transformants showed a similar chlorophyll index after salinity treatments with AtBI-1. Furthermore, we compared the effects of salinity stress on leaves and roots by examining the hormone levels of abscisic acid (ABA), jasmonic acid (JA), gibberellic acid (GA3), and zeatin in transformants compared to the control. With the exception of phytohormones, stress-induced changes in hormone levels putatively related to stress tolerance have not been investigated previously. Hormonal level analysis confirmed the lower rate of stress in the transformants compared to the control. The levels of ABA and JA in OsSAP and AtBI-1 transformants were similar, where stress rates increased after one week and decreased after a two week period of drought; there was a slightly higher accumulation compared to the control. However, a similar trend was not observed for the level of zeatin, as the decrease in the level of zeatin accumulation differed in both OsSAP and AtBI-1 transformants for all genotypes during the early period of salinity stress. The GA3 level was detected under normal conditions, but not under salinity stress.