• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.402-408
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• 2005

The purpose of this study was to investigate the effects of estrogen deficiency on pulpodentinal complex of tooth in ovariectomized rats. Thirty female Sprague-Dawley rats, 10 weeks old, were used. Rats were grouped into two groups. One group (n = 15) was subjected to sham surgery (SHAM) and the other group (n = 15) was ovariectomized bilaterally (OVX). Animals were sacrificed 12 weeks later, and their mandibular molars and associated periodontal supporting tissues were dissected out, and fixed in $10\%$ buffered formalin. For comparison of groups, immunostained for osteonectin. Histomorphometrical measurement of change of teeth was performed using an image analysis system and paired t-test was used and the level of significance for overall differences was set at p < 0.05. In immunostaining of osteonectin, they were significantly different from each other. The predentin thickness in OVX rats was wider than in SHAM rats. And in SHAM rats, osteonectin was more specifically stained in predentin areas than in OVX rats. These results indicate that estrogen deficiency increased the unmineralized predentin areas and decreased osteonectin content in pulpal tissues in rats. If our result is applicable to human studies, odotoblast is affected by estrogen deficiency.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.115-121
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• 1996

To investigate gestational profiles in gene expression of placental lactogen I fpL4), PL-lI and Pit-1, RNA samples were extracted from the placentas of pregnant day 12 to 20 at 2 day intervals. Northern blots showed changes in gene expression of PL4, - 11 and Pit-i. Sizes of PL-l and -II mRNA were changed and amounts of PL-I, -H and Pit-1 mRNA increased during progress of gestation. To examine the effect of estrogen on the gene expression of PL-I, -Il and Pit-1, pregnant female rats were ovariectomized (OVX) and daily injected with estradiol (OVX + E). OVX markedly lowered the amount of PL4 and 41 mRNA, and shifted niRNA size from 1 kb to i 3 kb in PL-l mRNA and 0.6 kb to i kb in PL-ll mRNA, respectively. OVX had no effect on the mRNA size of Pit-1, but markedly attenuated Pit-1 mRNA level. Estrogen injection reversed the effect of OVX on the size-shift but not on the amount of PL4 and -Il mRNA. Replacement of E partially recovered OVX-induced inhibition of Pit-i mRNA level. Present results suggest that estrogen may play a pivotal role on the gene expression of PL-l and -Il such as alternative RNA splicing and/or polyadenylation, and Pit-1 may be involved in the gene expression of PL-l and 41 by estrogen.

• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.3.1-3.11
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• 2018

This study aimed to verify the effects of estrogen on the onset and development of adolescent idiopathic scoliosis and the mechanisms associated with these effects by constructing a pubescent bipedal rat model. Experiments were conducted to investigate whether scoliosis progression was prevented by a Triptorelin treatment. One hundred twenty bipedal rats were divided into female, OVX (ovariectomy), OVX + E2, Triptorelin, sham, and male groups. According to a spinal radiographic analysis, the scoliosis rates and curve severity of the female and OVX + E2 groups were higher than those in the OVX, Triptorelin, and male groups. The measurements obtained from the sagittal plane of thoracic vertebrae CT confirmed a relatively slower growth of the anterior elements and a faster growth of the posterior elements between T11 and T13 in the female and OVX + E2 groups than in the OVX and Triptorelin groups. Histomorphometry and immunohistochemistry revealed a significantly longer hypertrophic zone of the vertebral cartilage growth plates that expressed more type X collagen and less type II collagen in the OVX and Triptorelin groups than in the female and OVX + E2 groups. Ki67 immunostaining confirmed an increase in the proliferation of vertebral growth plate chondrocytes in the OVX group compared with the female and OVX + E2 groups. In conclusion, estrogen obviously increased the incidence of scoliosis and curve severity in pubescent bipedal rats. The underlying mechanism may be a loss of coupling of the endochondral ossification between the anterior and posterior columns. Triptorelin decreased the incidence of scoliosis and curve magnitudes in bipedal female rats.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.4
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• pp.1-11
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• 2012

Objectives: Osteoporosis, which occurs after menopause, is a kind of metabolic bone disorder. It develops when the bone mass begins to decrease radically, and its main symptoms are bone fracture and height-shortening. This thesis aims at what effects the Cuscutae Semen Extract(CSE) has on the prevention of osteoporosis in SD-rat that is caused by ovariectomy. Methods: The 24 female white rats, after removing their ovaries, were divided into the Normals, the Control group, and the CSE administrated group. For the next 8 weeks, distilled water to the normals and the control, and the CSE(45.9 mg/100 g) to the CSE administrated group were given in the mouths of them. After 8 weeks the rats were sacrificed. Weight, albumin, aspartate aminotransferase, alanine aminotransferase, total-cholesterol, triglyceride, phosphorus, calcium, tetraiodothyronine, estradiol, the weight of the femur, the amount of tibia ash, the area of trabecular bone, and the thickness of trabecular bone were measured. Results: The serum analysis shows that the calcium and phosphorous of the CSE administrated group significantly increased compared to that of the control group. Aspartate aminotransferase, alkalinephosphatase, total cholesterol, tetraiodothyronine of CSE group were decreased, but not so significant. Albumin, alanine aminotransferase, triglyceride and estradiol of the group showed the tendency to increase, but the significance wasn't admitted. Regarding the variation of bone, the femur weight and the ash content of tibia, CSE group was more increased than the control group but the significance wasn't admitted. The histological observation shows that the trabecular thickness was more increased than the control group, and trabecular area increased significantly compared to those of the control group. The number of osteoclast and osteoblast area of the CSE groups decreased significantly compared to those of the control group. Conclusions: From the result of the above study, CSE should be effective for the osteoporosis cure and precaution and deeper study through bedside and clinical demonstration is much needed from now on.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.225-235
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• 1993

Pituitary LH release has been known to be regulated by the hypothalamic gonadotropin releasing hormone (GnRH) and the gonadal steroid hormones. In addition, neurotransmitters and neuropeptides are actively involved in the control of LH secretion. The alteration in LH release might reflect changes in biosynthesis and/or posttranslational processing of LH. However, little is known about the mechanism by which biosynthesis of LH subunits is regulated, especially at the level of transcription. In order to investigate if ovarian steroid hormones regulate the LH subunit gene expression, ${\alpha}\;and\;LH{\beta}$ steady state mRNA levels were determined in anterior pituitaries of ovariectomized rats. Serum LH concentrations and pituitary LH concentrations were increased markedly with time after ovariectomy. ${\alpha}\;and\;LH{\beta}$ subunit mRNA levels after ovariectomy were increased in a parallel manner with serum LH concentrations and pituitary LH contents, the rise in $LH{\beta}$ subunit mRNA levels being more prominent than the rise in ${\alpha}\;subunit$ mRNA. ${\alpha}\;and\;LH{\beta}$ subunit mRNA levels in ovariectomized rats were negatively regulated by the continuous treatment of ovarian steriod hormones for $1{\sim}4\;days$ and $LH{\beta}\;subunit$ mRNA seemed to be more sensitive to negative feedback of estradiol than progesterone. Treatment of estrogen antagonist, LY117018 or progesterone antagonist, RU486 significantly restroed LH subunit mRNA levels as well as LH release which were suppressed by estradiol or progesterone treatment. These results suggest that ovarian steroids negatively regulate the LH synthesis at the pretranslational level by modulating the steady state levels of ${\alpha}\;and\;LH{\beta}\;subunit$ mRNA and $LH{\beta}\;subunit$ mRNA seemed to be more sensitive to negative feedback action of estradiol than progesterone.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.993-1005
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• 1996

This study was implemented in order to investigate the effects of dietary calcium-salt, estrogentreatment, and estrogen/calcium treatment on bone metabolism. Ovariectomized rats were used as animal models. Female Sprague-Dawley rats with a body weight of 250~280g were underwent ovariectomy or sham-operation. The ovariectomized rats were divided into 9 different experimental groups including the saline-treated group, the estrogen-treated group, the high calcium salt-treated group, and the estrogen/calcium treated groups and fed for 6 weeks. Creatinine and hydroxyproline in urine were analyzed. Creatinine, calcitonin, osteocalcin, alkaline phosphatase and parathyroid hormone in plasma were also determined. The results of the experiment are as follows : The ovariectomy caused a significant increase in the level of food intake, food effciency ratio and body weight gain in comparison with sham-operation. The overall food intake, food effciency ratio and body weight gain were significantly decreased by estrogen. The ovariectomized animals developed obesity as a result of increased food intake. In addition, estradiol injections suppressed food intake with a concomitant loss in body weight. The level or urinary hydroxyproline, as an indicator or bone resorntion, was higher in the ovariectomized rats compared to sham-opertion, while these decresed in the estrogen/calcium treated group. Parathyroid hormone and calcitonin in the plasma, that were used as the indicator of calcium homeostasis, parathyroid hormone higher in the ovariectomized rats compared to sham-operation. It was lowered by estrogen and high calcium treated groups; thus, estrogen and estrogen/calcium treated groups were decreased by 32% compared to saline treated group. Osteocalcin and alkaline phosphatase which are indicators of bone formation, were significantly higher in ovariectomized group, while this showed to be decreased in the estrogen and the ostrogenicalcium treated groups. Estrogen and estrogen/calcium in ovariectomized rats resulted in lower bone loss. However, estrogen treated group its gradual reduction showed little effect on bone loss, while the gradual reduction of estrogen had a preventive effect on bone loss when the treatment was combined with calcium intensification.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.657-661
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• 2001

Osteoporosis that is associated with ovarian hormone deficiency following menopause (postmenopausal osteoporosis) is by far the most common cause of age-related bone loss. Isoflavone has been reported as a natural substance that possibly minimizes bone loss in postmenopausal women. This study was conducted to investigate the preventing, treating effects of isoflavone on bone loss in ovariectomized rats. 120 Sprague Dawley rats of 13 week-old were devided into 2 groups, a treatment group and prevention group. Each group was consisted of six subgroups; control (CON), sham operated (SH) or ovariectomized (OVX) and isoflavone supplemented goups: OVX+0.25mg isoflavone/kg diet (OL), OVX+0.8mg isoflavone/kg diet(OM) and OVX+2.5mg isoflavone/kg diet(OH). to study the preventing effects of isoflavone on bone loss, OL, OM and OH groups were fed with isoflavone from 4 days after ovariectomization. Treating effects of isoflavone on bone metabolism were investigated with OL, OM, OH groups supplemented with isoflavone from 8 weeks after ovariectomization. Isoflavone supplementation continued for 8 weeks. At 8 weeks after ovariectomization significant increase in alkaline phosphatase occurred comparing with CON and SH group. By isoflavone supplementation from 4 days after ovariectomy alkaline phosphatase and urinary hydroxyproline were lowered and bone mineral density, bone strength of the femur and tibia and bone dry weight were slightly enhanced with no significant difference. Isoflavone supplemented group at the level of 0.8mg/kg diet (OM group) had significantly lower serum alkaline phosphatase, urinary hydroxyproline, and higher strength of femur than OVX group. Groups with isoflavone supplementation fro 8 weeks after ovariectomy had lower level of serum alkaline phosphatase, urinary hydroxyproline than OVX group. Bone mineral density, bone dry weight and bone strength of the femur and tibia were slightly enhanced by isoflavone supplementation. However there was no significanct difference between OVS ad isoflavone supplementation groups. The results suggest that isoflavone might have potential role for preventing postmenopausal bone loss. Isoflavone supplementation at early stage of postemenopause may be beneficial to age-related bone health.

• Clinical and Experimental Reproductive Medicine
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• v.11 no.2
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• pp.41-49
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• 1984

It has been well known that ovarian steroids, estradiol and progesterone play an important role in the endometrial preparation for the implantation process. The present investigation was undertaken to correlate function of ovarian steroids with cAMP concentrations in uterine tissues of rat during the various stages of the preimplantation period. Rats ovariectomized on day 2 were treated with estradiol or/and progesterone on day 3 or on day 4 and cAMP concentrations in uterine tissues were determined by competitive protein - binding assay in control - and steroid treated - ovariectomized rats. The results obtained are as follows; 1. In control rats, cAMP concentrations in uterine tissues were decreased with preimplantation period proceeded whereas cAMP concentrations were increased and showed the highest levels on day 6 in ovariectomized rats. 2. In rats treated with progesterone only or progesterone with estradiol after ovariectomy, cAMP concentrations on day 6 were lower than those of ovariectomized control but higher than those of intact control rats while estradiol only treatment decreased cAMP concentrations on day 3 and day 6, compared with those from intact- and ovariectomized-controls. It is, therefore, concluded that the concentrations of cAMP in uterine tissues were lower in estrogen-treated rats than in ovariectomized rats, suggesting the involvement of cAMP in the regulation of uterine tissue differentiation.

• Journal of Life Science
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• v.18 no.2
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• pp.249-254
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• 2008

This study was performed to investigate the effects of sea tangle (ST) extracts on serum lipid concentration in ovariectomized rats. Weight-matched female Sprague-Dawley strain rats were assigned to four groups. Three groups were surgically ovariectomized (OVX). The fourth group was sham operated. Rats were randomly assigned to the following groups: sham-operated rats (Sham), ovariectomized control rats (OVX-control), ovariectomized rats supplemented with ST at 50 mg/kg body wt (OVX-ST50) and ovariectomized rats supplemented with ST at 200 mg/kg body wt (OVX-ST200). The activities of serum GOT and GPT were increased by ovariectomized. The serum GOT levels in OVX-ST50 and OVX-ST200 groups were decreased than OVX-control group. But GPT level was only decreased in the serum of OVX-ST200 group. Serum total cholesterol and triglyceride contents decreased in sham group compared with OVX-control group by ovariectomy. Six weeks feeding of ST extract resulted in a significant lowering of serum triglyceride and lowering tendency of total cholesterol Level. The serum HDL-cholesterol was higher in ST groups than OVX-control group. These results suggest that the beneficial effect of ST extract may be used to possibly improve on the lipid metabolic syndrome of menopausal women.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.667-672
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• 2015

Cynanchum wilfordii and Phlomis umbrosa Turcz. are known to contain isoflavone, a representative phytoestrogen. This study was performed to determine whether the extract mixture of C. wilfordii and P. umbrosa Turcz. would induce an estrogenic effect in ovariectomized rats. The extracts were administered to the ovariectomized rats at 30, 60, 120 mg/kg per day for 4 weeks, respectively. They showed no estrogenic effect, which was indicated by the decrease in uterus wall thickness as well as the increase in body weight and the level of cholesterol and triglyceride. The extracts also had no effect on the concentrations of estrogen and growth hormone in the serum. However, the increase in alkaline phosphatase activity, which leads to protection against the bone loss caused by ovariectomy, was noted on administration of the extract. Therefore, it seemed that the extracts of C. wilfordii and P. umbrosa Turcz. had no estrogenic effect in rats.