• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.66-67
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• 2003

It is well known that osteoblasts and osteoc1asts playa key role in bone metabolism. They involve in osteoformation or bone destruction which are ragulated by various factors such as thyroid hormone, parathyroid hormone, estrogen, growth factor and cytokine. Recently, it is demonstrated that oxidative stress is one of pathological factors in bone metabolism, but it is left unknown about mechanism between oxidative stress and bone metabolism.(omitted)

• Korean Journal of Poultry Science
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• v.24 no.2
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• pp.85-90
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• 1997

An experiment was conducted to investigate the relationship between blood hormone levels and light cycle on performance of Korean native chicken. One hundred and two Korean native chickens were grouped into three treatments of natural light cycle (Control), 13L:11D (T2), and 16L:8D (T3). The egg production, egg weight, feed intake, serum melatonin and estrogen level were periodically measured from 22 to 34 weeks, respectively. The laying rates of T2 and T3 were significantly higher than that of the Control (P

• Clinical and Experimental Reproductive Medicine
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• v.18 no.2
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• pp.197-199
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• 1991

The role of estrogen in calcium metabolism has not been well documented. To further investigate the effects of endogenous estrogen on the calcium regulating hormones in women, we correlated the changes of estrogen level with those of calcium regulating hormones during ovulation induction in 12 hypogonadal and 8 normally menstruating women. During ovulation induction, the serum leveles of estradiol rose from 40.0 to 831.0pg/ml. There were no significant changes in the serum leveles of total calcium, inorganic phosphorus, parathyroid hormone, calcitonin. However, 1, $25-(OH)_2D_3$ rose significantly from 31.0 to 47.2pg.ml as the endogenous $E_2$ increaed (p<0.005).

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.475-479
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• 1997

A decrease in the circulating levels of estrogen, occuring as a consequence of post menopausal decline or from surgical ovariectomy, results in an accelerated loss of bone. Estrogen has been shown to stimulate lysyl oxidase activity, and the treatment with estrogen increased the pyridinium content of cortical bone. a trivalent mature cross-links collagen fibrils named pyridinoline, which is especially abundant in collagen of cartilage and bone, markedly increases with growth in humans and rats. The main aim of this study was to examine the increased bone loss caused by ovariectomy through monitoring the concentrations of the collagen and the pyridinium cross-links of collagen, pyridinoline. The ovariectomized rats, 4 weeks old, were divided at random into two or three groups of 5. Ovariectomies were carried out on both of the saline-treated group(OVX(NH)) and the estrogen-treated group(OVX(H)) using the dorsal approach and sham operations were performed on the sham-operated group(sham). They were maintained under identical conditions for 4 or 8 weeks and were allowed free access to food and water. it was observed that there was no significant difference between the control group and the sham-operated group, however, the control group had a higher content of collagen than the saline-treated group after 4 weeks and 8 weeks. Based on these results, iot is supposed that estrogen can enhance collagen synthesis and affects the pyridinoline formation in collagen fibrils through stimulating lysyl oxidase activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48
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• pp.31-40
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• 2003

Phytoestrogens are oestrogenic compounds found in plants and consist of isoflavones, lignans, and coumestans. The structural similarity of phytoestrogens to endogenous oestrogens has promoted the hypothesis that phytoestrogens exert hormonal or anti-hormonal effects relevant to the risk of hormone-dependent disease and/or their suitability as a dietary alternative to hormone replacement therapy. Epidemiological studies suggest that food stuffs containing phytoestrogens may have a beneficial role in protecting against a number of chronic disease and conditions. It is thought that these estrogen-like compounds may protect against chronic diseases, such as hormone-dependent cancers, cardiovascular disease and osteoporosis. Furthermore, phytoestrogens are used as a natural alternative to hormone replacement therapy and to reduce menopausal symptoms. Phytoestrogens are considered good candidates for use in natural therapies and as chemopreventive agents in adults. However safe and efficacious levels have yet to be established.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.237-248
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• 2001

Biomechanical reactions of tooth movement are the combination of bone formation and resorption, in which many paracrine factors are involved. The sex hormone is one of the paracrine factors and the sex hormonal level of an adult female vanes according to the body condition, e.g. mensturation, pregnancy, postmenopause, etc. Although the exact mechanism is not clarified yet, estrogen and progesterone are known to regulate the function of osteoblast. Again osteoblast is reported to affect the function of osteoclast. The purpose of this study is to determine the influence of the female sex hormone, estrogen and progesterone, on the cell proliferation and activity of HOS and ROS17/2.8 cell line. The observed results were as follows. 1. Estrogen inhibited HOS cell proliferation and promoted ROS17/2.8 cell proliferation. 2. Estrogen increased the activity of alkaline phosphatase of HOS cell and reduced the activity of alkaline phosphatase of ROS17/2.8 cell. 3. Progesterone inhibited the proliferation of HOS and ROS17/2.8 cell, but had no influence on the activity of alkaline phosphatase. 4. Estrogen and progeterone did not have any particular effects on the activity of super oxide, nitric oxide and gelatinase of HOS and ROS17/2.8 cell.

• Toxicological Research
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• v.26 no.4
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• pp.237-243
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• 2010

Endocrine disrupting chemicals (EDCs) have been shown to interfere with physiological systems, i.e., adversely affecting hormone balance (endocrine system), or disrupting normal function, in the female and male reproductive organs. Although endocrine disruption is a global concern for human health, its impact and significance and the screening strategy for detecting these synthetic or man-made chemicals are not clearly understood in female and male reproductive functions. Thus, in this review, we summarize the interference of environmental EDCs on reproductive development and function, and toxicological mechanism(s) of EDCs in in vitro and in vivo models of male and female reproductive system. In addition, this review highlights the effect of exposure to multiple EDCs on reproductive functions, and brings attention to their toxicological mechanism(s) through estrogen receptors.

• Natural Product Sciences
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• v.1 no.1
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• pp.17-24
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• 1995

The effects of orchildectomy with/without testosterone replacement in wale rats, and ovarectomy with estrogen replacement in female rats on lipid peroxidation were studied in male and female rats fed with diets fortified with 20% w/w, soybean oil or palm oil for 4 months. Serum, liver and heart homogenates were assayed for malonaldehyde and conjugated diene levels. Orchidectomy was found to reduce levels of lipid peroxidation products in the serum, liver and heart. Testosterone replacement did not increase the lipid peroxidation products to levels in the non-orchildectomised rats, while estrogen did not influence lipid peroxidation significantly. Palm oil decreased, but soybean oil increased lipid peroxidation in the liver and heart of both the castrated and sex hormone-replaced male and female rats.

• 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.

• Animal cells and systems
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• v.5 no.1
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• pp.51-57
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• 2001

We have previously shown that oocyte maturation is induced by an immobilized progesterone, progesterone-3-carboxymethyloxime - bovine serum albumin conjugate (P-BSA) in Rana dybowskii. In this study, we confirmed the maturation inducing activity of P-BSA on Xenopus oocyte and examined the binding character of the immobilized progesterone on the surface of Xenopus oocytes after removal of the vitelline layer. P-BSA induced maturation of Xenopus oocytes but E-BSA failed to do so as observed in Rana. Binding of the immobilized progesterone, fluorescein isothiocyanate-labeled progesterone-3-0-carboxymethyloxime-BSA (P-BSA-FITC) on the devitellined oocytes surface was examined by fluorescence confocal microscopy. The binding affinity of P-BSA-FITC to the devitellined oocyte was higher than that of estrogen-BSA-FITC (E-BSA-FITC) or testosterone-BSA-FITC (T-BSA-FITC). The binding disappeared in the presence of excess free progesterone but not in the presence of free estrogen. Maximum binding occurred after two-hours of incubation with P-BSA-FITC at pH 7.5. Stronger binding occurred in oocytes at stage Vl than stage IV, and in vitro treatment of hCG enhanced the binding. Taken together, these results suggest that a specific receptor for progesterone exists on the plasma membrane of Xenopus oocytes and that progesterone acts initially on this putative receptors and triggers generation of membrane-mediated second messengers during the early stage of oocyte maturation In amphibians.