• Archives of Pharmacal Research
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• 제20권6호
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• pp.579-585
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• 1997

To gain further insight into the mechanism of action of antiestrogens, we examined the interaction of antiestrogen with the estrogen receptor system and with estrogen- noncompetable antiestrogen binding sites. In addition to binding directly to the estrogen receptor, antiestrogens can be found associated with binding sites that are distinct from the estrogen receptor. In contrast to the restriction of estrogen receptors to estrogen target cells, such as those of uterus and mammary glands, antiestrogen binding sites are present in equal amounts in estrogen receptor-positive and -negative human breast cancer cell lines, such as MCF-7, T47D, and MDA-MB-231 that differ markedly in their sensitivity to antiestrogens. In order to gain greater insight into the role of these antiestrogen binding sites in the action of antiestrogens, we have examined the biopotency of different antiestrogens for the antiestrogen binding sites and that is CI628 > tamoxifen > trans-hydroxy tamoxifen > CI628M > H1285 > LY117018. This order of affinities does not parallel the affinity of these compounds for the estrogen receptor nor the potency of these compounds as antiestrogens. Indeed, compounds with high affinity for the estrogen receptor and greatest antiestrogenic potency have low affinities for these antiestrogen binding sites. Antiestrogenic potency correlates best with estrogen receptor affinity and not with affinity for antiestrogen binding sites. In summary, our findings suggested that interaction with the estrogen receptor is most likely the mechanism through which antiestrogens evoke their growth inhibitory effects.

• 대한약리학회지
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• 제26권2호
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• pp.167-176
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• 1990

비스테로이드성 항에스트로젠제는 표적기관에서 estrogen 수용체와 상경적으로 결합하므로써 estrogen의 작용을 억제하는 것으로 알려져 있다. 비스테로이드성 항에스트로젠제는 대체로 triphenylethylene계로서 tamoxifen, clomiphene, LYl17018등이 있으며 표적기관에서 estrogen의 작용을 억제하기 때문에 estrogen과 관련된 질환을 치료하는데 이용되어 오고 있다. 본 연구에서는 생후 21-23일된 미성숙 흰쥐를 재료로 항에스트로젠제중 tamoxifen과 LY117018이 자궁세포 성장에 어떠한 영향을 미치며 어떠한 기전으로 estrogen의 작용을 길항하는지를 규명하고자, 항에스트로젠제가 estrogen작용의 중요 지포에 미치는 영향을 비교 관찰하여 다음과 같은 결과를 얻었다. Tamoxifen과 LY117018은 자궁세포에서 estrogen의 영향이 없는 경우에는 estrogen agonist로, estrogen작용하에서는 estrogen antagonist로서 작용하였다. Estrogen 작용의 여러 가지 지표에 대해 tamoxifen이 LY117018보다 agonistic effect는 더 컸으나, antagonistic effect는 LY117018이 더 큰 것으로 나타났다. Estrogen 수용체에 대한 결합능은 LY117018이 estradiol보다는 약간 낮았으나 용량에 비례하여 estrogen 수용체와 결합하였다. 그러나 tamoxifen은 estrogen 수용체에 대한 결합이 아주 낮았다. Estrogen 수용체에 대한 binding affinity는 estradiol(100%), LY117018(77%), tamoxifen(6.3%) 순으로 나타났다. 항에스트로젠제의 생체내 투여는 estrogen 존재 유무에 따라 estrogen 수용체 농도에 agonist 또는 antagonist로 작용하였다. 항에스트로젠제의 단독투여는 progesterone 수용체 생성을 증가시키나, estrogen에 의하여 유도된 progesterone 수용체 생성을 억제하였다. 이상의 결과로 보아, tamoxifen과 LY117018은 estrogen유무에 따라 흰쥐 자궁세포에서 estrogen antagonist로서 뿐만 아니라 agonist로서도 작용함을 알 수 있다. 그러나 estrogen수용체와의 결합능력이 아주 낮은 tamoxifen은, 용량에 비례하여 estrogen수용체에 결합하므로써 작용하는 LY117018과는 다른 기전으로 작용하는 것으로 생각된다.

• Archives of Pharmacal Research
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• 제24권6호
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• pp.473-484
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• 2001

There is clearly a need for novel breast cancer chemopreventive agents with enhanced potency and specificity with tittle or no side effects. To this end, several new chemical moieties have been synthesized or isolated from natural sources. In this reviewal we have described some agents currently in use or under development for treatment or prevention of breast cancer, as well as our own strategies for the discovery of natural product modulators of estrogen biosynthesis and function. In particulars bioassay-guided fractionation of active plant extracts is a unique method for identifying agents with novel mechanisms of action, some of which should be useful for prevention of human cancer. Further, with the advent of combinatorial chemistry and high throughput screening, even greater progress may now be expected with natural product leads.

• 한국미생물·생명공학회지
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• 제35권2호
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• pp.81-97
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• 2007

Punica granatum, L. (Pomegranate) has 613 seeds which accidentally corresponds to the 613 commandments in the Bible. Accordingly, the fruit has been worshipped by the Jewish and other religious people from the ancient. Pomegranate's seed, peel and juice contain a variety of ethnomedical components so much as the sum of three kinds of other common fruits. The number of published papers related to the pomegranate in recent 7 years flourished 7 times more than before at the bases of Medline record. Since the containments of estrogen, as $17{\alpha}-estradiol,\;17{\beta}-estradiol$, estrone, and estradiol, etc., in pomegranate have been reported, public interests and commercial values of pomegranate arose considerably. The report was disproved later, however, merits of this fruit remained yet; clinical efficacy for preventing and remediating cancers including breast and prostate cancers by oral administration of the juice, seed oil, and peel extract is still believed to be true. In this review, target components of pomegranate such as antioxidants, anticancers, antiestrogens and ethnomedical components were analyzed and discussed along with examining its pharmaceutical efficacy and prescription to postmenopausal lesion, cardiosclerosis, cosmetic beautification, viral and allergic symptoms, and diabetes mellitus, etc.

• Animal cells and systems
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• 제15권3호
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• pp.189-196
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• 2011

We investigated the in vitro effects of nonylphenol (NP) and 3,3',4,4',5-pentachlorobiphenyl (PCB126) on steroidogenesis in redlip mullet, Chelon haematocheilus, oocytes. In experiment 1, we investigated the effects of NP and PCB126 on steroid production from exogenous steroid precursors. Vitellogenic oocytes (0.75 mm in diameter) were incubated with 10 and 100 ng/ml NP or PCB126 with $[^3H]17{\alpha}$-hydroxyprogesterone as a precursor. The major metabolites produced were androstenedione, testosterone (T), estrone, and estradiol-$17{\beta}$ ($E_2$). Both NP and PCB126 increased T production and decreased $E_2$ production, except for 100 ng/ml PCB126. In experiment 2, oocytes (0.65-0.75 mm in diameter) were exposed to NP and PCB126 at different concentrations (0.01, 0.1, 1, 10, and 100 ng/mL). After the incubation, T and $E_2$ production was measured by radioimmunoassay. NP inhibited $E_2$ production at concentrations of 0.01 and 0.1 ng/ml in 0.75-mm-diameter oocytes. NP at 1 and 100 ng/mL stimulated T production, but had no observable effect on $E_2$ production. PCB126 treatment did not affect $E_2$ production at any of the concentrations tested. NP alone at 0.1 ng/mL resulted in a significant decrease in $E_2$ production in 0.65-mm-diameter oocytes. PCB126 did not show any significant effects on either T or $E_2$ production at all concentrations tested. These results suggest that NP acts like an antiestrogen at lower concentrations (0.01-0.1 ng/ml) in vitellogenic oocytes of redlip mullet.

• The Korean Journal of Physiology
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• 제20권2호
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• pp.271-278
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• 1986

These studies were carried out to investigate the effects of the antiestrogens, LY-117018 and tamoxifen, on implantation in ovariectomized or intact adult rats. A Quantity of $80\;{\mu}g$ of LY-l17018 or tamoxifen was given to adult female rats on Day 1, 2, 3 and 4 of pregnancy and investigated the implantation sites on Bay 8 of pregnancy. The rats were ovariectomized at the first day of pregnancy and treated with various doses of LY-l17018 or tamoxifen together with progesterone daily from Day 2 to 8 of pregnancy and then investigated the implantation sites on Day 8 of pregnancy The results were summarized as follows; When a single dose of $80\;{\mu}g$ LY-l17018 and tamoxifen was given during the first 4 days of pregnancy, the implantation was intesively inhibited in the pregnant rat treated with LY-l17018 on Day 2 $(14.4{\pm}3.5%),\;3(16.3{\pm}5.3%)\;and\;tamoxifen\;on\;Days\;2\;(17.4{\pm}4.6%),\;3\;(16.3{\pm}2.8%)\;and\;4\;(13.9{\pm}3.5%).$ LY-l17018 was apt to inhibit more potently the implantation than tamoxifen except on Day 4 of pregnancy In rats ovariectomized on Day 1 of pregnancy and treated continucusly with 12? r9 of LY-117018 and tamoxifen together with progesterone showed the highest implantation rate, compared with the rats treated continuously with different doses of the two drugs. The correlation coefficients between the dosage of drugs and implantation rate were r= 0.91 (LY-117018), 0.51 (tamoxifen), respectively, except treatment with $625\;{\mu}g$ of the drugs. Tamoxifen was apt to stimulate the implantation more potently than LY-l17018 except groups treated with $625\;{\mu}g$ of the two drugs.

• Archives of Pharmacal Research
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• 제20권6호
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• pp.572-578
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• 1997

To gain further insight into how antiestrogens modulate cell function, the effects of antiestrogen on cell proliferation were studied in human breast cancer cells. We examined the effects of trans-tamoxifen on the proliferation of three human breast cancer cell lines that differed in their estrogen receptor contents. Trans-tamoxifen $(1{\mu}M)$ markedly inhibited the estrogen stimulated proliferation of MCF-7 human breast cancer cells that contained high levels of estrogen receptor $(1.15{\pm}0.03 pmole/mg protein)$ over that of control. In T47D cells that contained low levels of estrogen receptor $(0.23{\pm}0.05 pmole/mg protein)$, trans-tamoxifen $(1{\mu}M)$ showed minimal inhibition of estrogen stimulated cell proliferation over that of control. MDA-MB-231 cells, that contained no detectable levels of estrogen receptors, had their growth unaffected by trans-tamoxifen treatment. These results showed their sensitivity to growth inhibition by antiestrogen conrrelated well with their estrogen receptor content. Also we examined the effect of antiestrogen on cellular progestrone receptor level as well as plasminogen activator activity in MCF-7 cells. Trans-tamoxifen $(1{\mu}M)$ showed maximal inhibition of estrogen stimulated progestrone receptor level as well as plasminogen activator activity in MCF-7 cells that were stimulated by estrogen. It is not clear whether these inhibitions of progestrone receptor and plasminogen activator activity by estrogen are related to the antiestrogen inhibition of cell proliferation of MCF-7 cells. From the results of this study, it is clearly demonstrated that trans-tamoxifen is an antiestrogen in MCF-7 human breast cancer cells. Our data suggest that the biological effectiveness of trans-tamoxifen appear to result from its affinity of interaction with the estrogen receptor.

• Clinical and Experimental Reproductive Medicine
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• 제14권1호
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• pp.61-70
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• 1987

This study was carried out to investigate the effects of the antiestrogens, LY-117018 and tamoxifen on reproductive organ of ovariectomized immature rats and also to elucidate the mechanism of action of said compounds by bioassay. Each of LY-117018, tamoxifen and estradiol-17${\beta}$ was administered to ovariectomized immature rats at various dose levels. Forty hours after drug administration, tested rats were sacrificed and uterine wet weight, DNA and RNA contents in uterine and liver tissues were investigated. At the same time, uterine wet weight was also investigated with some other rats treated with 125${\mu}g$ of LY-117018 together with increasing doses of tamoxifen. Ovariectomized immature rats given 25${\mu}g$ single dose of each drug were sacrificed on Day 1, 2, 3, 4, and 5 after drug administration and uterine was weighed to estimate the duration of action of LY-117018 and tamoxifen. The results were summarized as follows: 1. The administration of LY-117018 or tamoxifen to ovariectomized rats increased uterine wet weight and DNA and RNA contents in uterine tissues with more increase in tamoxifen groups, but significant differences between groups treated at dose levels of 5${\beta}$ or more of both drugs were observed. Estradiol-17${\beta}$ groups showed significant increases in each group(P<0.01). 2. The administration of LY-117018 or tamoxifen to each group significantly increased DNA and RNA contents in liver tissues with more increase in tamoxifen groups. Estradiol-17${\beta}$ groups showed no significant differences between treatment groups of 5${\beta}$ or more. 3. Treatment with 125${\beta}$ of LY-117018 together with various doses of tamoxifen resulted in more increase of uterine wet weight than treatment with a single dose of LY-117018 or tamoxifen. 4. Treatment with 0.2${\beta}$ of LY-117018 or tamoxifen in ovariectomized rats decreased uterine wet weight,DNA and RNA contents in liver and uterine tissues compared with ovariectomized control. 5. The duration of effective action of LY-1l7018 and tamoxifen was 4 days or more. 6. There was significant difference(P<0.001) in uterine wet weight between Day 9after ovariectomy (two days after LY-117018 or tamoxifen treatment) and Day 10(63.7${\pm}$3.5mg, 39.2${\pm}$9.9mg, respectively).