• The Korean Journal of Physiology and Pharmacology
• /
• v.26 no.2
• /
• pp.113-123
• /
• 2022

Diarylpropionitrile (DPN), a selective agonist for estrogen receptor β (ERβ), has been reported to regulate various hormonal responses through activation of ERβ in tissues including the mammary gland and brain. However, the effect of DPN on melanogenesis independent of ERβ has not been studied. The aim of this study is to examine the possibility of anti-melanogenic effect of DPN and its underlying mechanism. Melanin contents and cellular tyrosinase activity assay indicated that DPN inhibited melanin biosynthesis in alpha-melanocyte stimulating hormone-stimulated B16F10 melanoma cell line. However, DPN had no direct influence on in vitro tyrosinase catalytic activity. On the other hand, 17β-estradiol had no effect on inhibition of melanogenesis, suggesting that the DPN-mediated suppression of melanin production was not related with estrogen signaling pathway. Immunoblotting analysis showed that DPN down-regulated the expression of microphthalmia-associated transcription factor (MITF), a central transcription factor of melanogenesis and its down-stream genes including tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. Also, DPN attenuated the phosphorylation of protein kinase A (PKA) and cAMP-response element-binding protein (CREB). Additionally, DPN suppressed the melanin synthesis in UVB-irradiated HaCaT conditioned media culture system suggesting that DPN has potential as an anti-melanogenic activity in physiological conditions. Collectively, our data show that DPN inhibits melanogenesis via downregulation of PKA/CREB/MITF signaling pathway.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.3
• /
• pp.378-384
• /
• 2012

In aquatic invertebrates, particularly marine gastropods, organotin compounds induce irreversible sexual abnormality in females, which is termed imposex, at very low concentrations. Organotin compounds are agonists for nuclear receptors such as RXRs and $PPAR{\gamma}$. However, the imposex phenomenon has not been reported to act as an antagonist on estrogen receptors in other species, including vertebrates and invertebrates. In order to gain insights into the antagonistic activity of organotin compounds on estrogen receptors (ERs), we examined the inhibitive effect of these compounds on estradiol-dependent ${\beta}$-galactosidase activity using the yeast two-hybrid detection system consisting of a combination of the human estrogen receptor ($hER{\beta}$) ligand-binding domain and the co-activator steroid receptor co-activator-1 (SRC1). Tributyltin-hydroxide (TBT-OH) and triphenyltin-chlorine (TPT-Cl) exhibited an inhibitive effect on $E_2$-dependent transcriptional activity, similar to antagonistic chemicals such as 4-hydroxytamoxifen (OHT) or ICI 182,780, at a very low concentration of $10^{-14}$ M TBT or $10^{-10}$ M TPT, respectively. The yeast growth and transcriptional activity with transcriptional factor GAL4 did not exhibit any effect at the tested concentration of TBT or TPT. Moreover, the yeast two-hybrid system using the interaction between p53 and the T antigen of SV40 large did not describe any effect at the tested concentration of OHT or ICI 182,780. However, the interaction between p53 and T antigen was inhibited at a TBT or TPT concentration of $10^{-9}$ M, respectively. These results indicate that TBT and TPT act as inhibitors of ER-dependent reporter gene transcriptional activation and of the interaction between $hER{\beta}$ LBD and the co-activator SRC1 in the yeast two-hybrid system. Consequently, our data could partly explain the occurrence of organotin compound-induced imposex on the endocrine system of mammals, including humans.

• Journal of Yeungnam Medical Science
• /
• v.9 no.2
• /
• pp.359-381
• /
• 1992

This study was designed to investigate the effect of diazepam on the spontaneous contraction and oxytocin induced contraction of the isolated rat uterus. Female rat(Sprague-Dawley) pretreated with oophorectomy and 4 days administration of estrogen, weighing about 200 g, was sacrificed by cervical dislocation, and the uteruses were isolated. A longitudinal muscle strip was placed in temperature controlled($37^{\circ}C$) muscle chamber containing Locke's solution and myographied isometrically. Diazepam inhibited the spontaneous contraction and oxytocin induced contraction of the isolated rat uterus in a concentration-dependent manner. GABA, muscimol, a GABA A receptor agonist, bicuculline, a competitive GAGA A receptor antagonist, picrotoxin, a non competitive GABA A receptor antagonist, baclofen, a GABA B receptor agonist, and delta-aminovaleric acid, a GABA B receptor antagonist, did not affect on the spontaneous and oxytocin induced contraction of the isolated rat uterus. The inhibitory actions of diazepam on the spontaneous and oxytocin induced contraction were not affected by all the GABA receptor agonists and antagonists, but exceptionally potentiated by bicuculline. This potentiation-effect by bicuculline was not antagonized by muscimol. In normal calcium PSS, addition of calcium restored the spontaneous contraction preinhibited by diazepam and recovered the contractile of oxytocin preinhibited by diazepam. A23187, a calcium inophore, enhanced the restoration of both the spontaneous and oxytocin induced contraction by addition of calcium. In calcium-free PSS, diazepam suppressed the restoration of spontaneous motility by addition of calcium but allowed the recovery of spontaneous motility to a considerable extent. Diazepam could not inhibit some development of contractility by oxytocin in calcium-free PSS, but inhibited the increase in contractility by subsequent addition of calcium. These results suggest that the inhibitory action of diazepam on the rat uterine motility does not depend on or related to GABA receptors and that diazepam inhibits the extracellular calcium influx to suppress the spontaneous and oxytocin induced contractilities.

• Journal of Nutrition and Health
• /
• v.37 no.9
• /
• pp.786-793
• /
• 2004

Women with menopause or rats with ovariectomy is associated with increased body weight, body fat and insulin resistance, which are components of metabolic syndrome. Increased prevalence of metabolic syndrome after menopause might be associated with mitochondrial dysfunction, since mitochondrial oxidative and phosphorylation activity is strongly correlated with insulin sensitivity. Although estradiol replacement prevents the metabolic syndrome, harmful effect of estradiol hampers the casual usage to prevent the metabolic syndrome. It has been reported that genistein has a mild estrogenic activity, decreases fat mass in mice and has an antidiabetic role in diabetic rats. Although insulin resistance is closely related to mitochondrial functions, there has not been yet any study in regard to the effect of dietary genistein on mitochondrial function in the insulin resistant female subjects induced by ovariectomy or similar situation. The present study investigated whether the supplementation of genistein in the high fat diet affected the mitochondrial function of high fat fed ovariectomized rats. Female Sprague Dawley rats (8 weeks old) were assigned to the following groups: sham-operated+ high fat diet (S, n=6); sham-operated + high fat diet with 0.1% genistein (S + G, n=7); ovariectomized + high fat diet (OVX, n=8); ovariectomized + high fat diet with 0.1% genistein (OVX+ G, n=8). Ovariectomy significantly increased body weight compared with S group. Genistein consumption in ovariectomized (OVX + G) rats decreased body weight gain compared with OVX rats. Liver weights were increased by ovariectomy. The hepatic mitochondrial protein density expressed as mg per g liver was lower in the OVX group than in the S group. However, OVX + G group showed the increased mitochondrial protein density similar to the level of S group. When mRNA levels of genes related to mitochondria such as peroxisome proliferator-activated receptor ${\gamma}$ coactivator 1 (PGC-1) and cytochrome c oxidase subunit III (COX III) were measured, there were decreases in the mRNA levels of PGC-1 and COX III in S + G, OVX and OVX + G group. The activity of cytochrome c oxidase was not different between groups. We could observe the decrease in succinate dehydrogenase (SDH) activity per g liver in OVX rats. Genistein supplement increased SDH activity. In conclusion, genistein supplementation to the OVX rats enhanced mitochondrial function by increasing mitochondrial protein density and SDH activity. The improvement in mitochondrial function by genistein can contribute to the improvement in metabolic syndrome.

• Environmental Mutagens and Carcinogens
• /
• v.24 no.3
• /
• pp.121-127
• /
• 2004

Cytochrome P4501B1(CYP1B1) is known to be inducible by xenobiotic compounds such as policyclic aromatic hydrocarbon(PAH) and dioxins such as 2,3,7,8-tetrachloro-dibenzo-p-dioxin(TCDD). And these induction of CYP1B1 is also regulated by many categories of chemicals. In order to investigate the effects of several chemicals on CYP1B1 gene expression in Hepa-I and MCF-7 cells, 5' flanking DNA of human CYP1B1 was cloned into pGL3 basic vector containing luciferase gene, and then transfected into these cells. After treatment of chemicals, the luciferase activity was measured. CYP1B1 enzyme metabolize PAHs and estradiol. CYP1B1 metabolize estradiol to 4-hydrozyestradiol that is considered as carcinogenic metabolite. Luciferase activity was induced about 20 folds over that control by 1 nM TCDD (2,3,7,8-tetrachloto-p-dioxin). Recent industrialized society, human has been widely been exposed to widespread environmental contaminants such as PAHs(polycyclic aromatic hydrocarbon) that are originated from the imcomplete combustion of hydrocarbons. PAHs are known to be ligands of the AhR(aryl hydrocarbon receptor). Induction of cytochrome P4501B1(CYP1B1) in cell culture is widely used as a biomarker for PAHs. Therefore we have studied the effect of PAHs in the human breast cancer cells MCF-7 to evaluate bioactivity of PAHs. We have used the United State of America EPA selected 13 different PAHs, PAHs mixtures and extracts from environmental samples to evaluate the bioassay system. We examined effects of PAHs on the CYP1B1-luciferase reporter gene and CYP1B1 mRNA level. Benzo(k)fluoranthene and dibenzo(a, h)anthracene showed strong response to CYP1B1 promoter activity stimulation, and also CYP1B1 mRNAs increase in MCF-7 cells in a concentration-dependent manner. Acenaphthene, anthracene, benzo(b)fluoranthene, fluorene, fluoranthene, anphthanlene, pyrene, phenanthrene and carbazole were weak responders in MCF-7 cells. RT-PCR analysis indicated that PAHs significantly up-regulate the level of CYP1B1 mRNA.

• The Korean Journal of Pesticide Science
• /
• v.8 no.2
• /
• pp.95-102
• /
• 2004

The present study was conducted to test and evaluate estrogenic effect of 17 pesticides including benomy1 and carbaryl, being suspected as endocrine disrupting chemicals. For estrogenic effect examination, luciferase assay were achieved with human ovarian cancer cell, BG1Luc4E2. Estrogenic effects of cypermethrin, dicofol, endosulfan, esfenvalerate, and fenvalerate were observed at the concentration of $10^{-5}$ M by estrogen receptor binding assay. Relative luciferase potency and relative luciferase effects compared with $10^{-10}$ M 17 $\beta$-estradiol were $10^{-5}$, 56% for dicofol, and $10^{-5}$, 72% for endosulfan, respectively. Estimated maximum daily intake for pesticides was calculated from maximum residue limit of agricultural commodity and food consumption was 1.2298 mg/person. Theoretically calculated blood estrogen level from dietary intake for pesticides based on MRL in Korea, 3.075 ng/L was equivalent to 15% of estrogen concentration in normal blood, but practical monitoring data, 0.01938 ng/L was equal to 0.09693% of estrogen concentration in normal blood.

• The Korean Journal of Zoology
• /
• v.32 no.3
• /
• pp.281-289
• /
• 1989

The present study was disigned to determine the concentration of bioavailable steroid hormones in the atretic follicular fluid (FF). The concentradons of progesterone (P), testosterone (T), estradiol (E), androstenedione (A), and 5-$\alpha$ dihydrotestosterone (DIlT) were determined by the established methods of luminescent immunoassay (LIA) or radioimmunoassay (RIA). Concentrations of T, A and Diff in human FF from smail (< 6 mm). medium (8-15 mm), and large (> 15 mm) atretic follicles were significandy higher than those of normal ones (p < 0.01). However, the levels of T, A and DHT in smail atretic foflicle were significandy lower than those found in normal one. The concentrations of P in atretic FF from porcine small (< 3 mm), medium (4-6 mm), and large (> 7 mm) follicles were not different from that of normal ones. However, the concentration of E in atretic forncles of each group was significantly lower than that of normal group (p < 0.001 in each group). On the other hand, the percentages of bioavailable T (BI) in human FF were significandy (p <0.001) higher than those in normal groups. The BT in normal or atretic FF was more than 90 % of total T. The present result demonstrates that the bioavailable androgen, but not E levels in atretic follicles is higher than that of normal one, and that the atretic mechanism might be dependent on the ovarian forncle size in the developmental stage and on the animal model system. Moreover, the present study suggests that the steroids found in the FF are the bioavailable forms and the concentration of BT in FF could be used as one of the valuable criteria classifying the ovarian atretic follicle.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.35 no.1
• /
• pp.31-37
• /
• 2013

Purpose: Maxilla and mandible have different patterns of cortical and trabecular bone and different bone mineral densities, even though both are components of the jaw bone. However, cellular differences between maxilla- and mandible derived osteoblasts (OBs) have rarely been studied. We hypothesize that maxilla- and mandible-derived OBs show different responses to $17{\beta}$-estradiol (E2), which is one of the critical factors for bone formation. This study compares skeletal site-specific cell responses between maxilla- and mandible-derived human OBs to E2. Methods: Maxilla- and mandible-derived OBs derived from an identical donor were separately isolated from a total of five normal healthy subjects aged 18~44 years old, cultured with a treatment of 100 nM estrogen. The responses between maxilla- and mandible-derived OBs to E2 were evaluated and compared using cell proliferation, alkaline phosphatase (ALP) activity and gene expression of osteoprotegerin (OPG), ALP, insulin-like growth factor-1 (IGF-1), and estrogen receptor ${\alpha}$ ($ER{\alpha}$). Results: E2 did not have any distinct effects on the proliferation of both types of OBs. Mandible-derived OBs exhibited higher ALP activity than maxilla-derived OBs in the non-treated condition, which was common in all tested individuals. ALP activities of both types of OBs showed a minor increasing tendency with the treatment of E2, even though there was no statistical significance in some specimens. The gene expression of OB by E2 was diverse, depending on the individuals. There was increased expression of OPG, IGF-1, or $ER{\alpha}$ gene in the part of subjects, which was more repeated in maxilla-derived OBs. In particular, OPG or ALP induction by E appeared less frequently in mandible-derived OBs. Conclusion: Current results revealed that E2 affects maxilla- and mandible-derived OBs into facilitating the osteogenic process despite individual differences. Mandible-derived OBs are less sensitive to bone-forming gene expression by E2.

• Korean Journal of Veterinary Research
• /
• v.36 no.1
• /
• pp.93-99
• /
• 1996

This study was designed to investigate the effect of estrogen(Est) on the progestcrone(Prog) target cells by autoradiography. The spayed 16 mice(ICR, approximately 18~25g) were randomly alloted into 3 groups. $^3H$-Prog-treated group were injected with $40{\mu}Ci$ of $^3H$-Prog/mouse/day for 1 day, Est + $^3H$-Prog-treated group with $20{\mu}Ci$ of $17{\beta}$-Est/mouse/day for 3 days and then with $40{\mu}Ci$ of $^3H$-Prog/mouse at 4th day, and Est+$^3H$-thymidine(TdR)-treated group with $20{\mu}g$ of $17{\beta}$-Est/mouse/day for 3 days and then $80{\mu}Ci$ of $^3H$-TdR/mouse at 4th days. 1. Mice uteri of both Est+$^3H$-Prog-treated group and Est+$^3H$-TdR-treated group were hypemophied in gross finding and the endometrium and myometrium were thickened in microscopic findings. These findings were confirmed that Est enlarged the uteri of mice. 2. Cryo-preparations of mice organs were processed for autoradiography using Kodak NTB-2 emulsion following Kodak D-19 developer and hematoxylin counterstain. In each group, the number values of silver grain distribution appeared to be higher in the $^3H$-Prog-treated group than in the Est+$^3H$-Prog-treated group. It was considered that Est and Prog inhibit each other in action. 3. In both $^3H$-Prog-treated group and Est+$^3H$-Prog-treated group, the uteri have highest distribution rates of silver grains than in other organs, and the cerebral neurons, hepatocytes, bronchiolar epithelial cells and splenic reticular cells also contained some silver grains. 4. The orders of the cell types with more number of silver grains in the uteri were stromal cells, glandular epithelial cells, luminal surface cells and muscular cells and also were as above orders in distribution of proliferating cell type by $^3H$-TdR.

• The Korean Journal of Physiology and Pharmacology
• /
• v.2 no.4
• /
• pp.493-501
• /
• 1998

The most significant direct role of estrogen in vivo is its ability to elicit receptor-mediated cellular proliferation in mammalian target tissues. However, the mechanism by which exogenously added estrogen causes the neoplastic transformation of renal cortical cells is yet to be uncovered. The present study was designed to evaluate interaction of $17{\beta}-estradiol\;(E_2)$ with epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) on proliferation and $P_i$ uptake in primary cultured rabbit renal proximal tubular cells in phenol red-free, hormonally defined-medium. $[^3H]-thymidine$ incorporation increased markedly by about 133% and 141% more in the presence of $10^{-9}\;and\;10^{-6}\;M\;E_2$, respectively, than that of control. Cell count was 162% and 143% greater in the presence of $10^{-9}\;and\;10^{-6}\;M\;E_2$ , respectively, compared with control. Among all time points examined, there was an increase in $[^3H]-thymidine$ incorporation in the presence of $10^{-9}\;M\;E_2$ at day 9 or 13, respectively. However, $E_2$ ($10^{-9}\;M$) significantly drove up cell count to 160% of that of control at day 13, while it had a slight but statistically insignificant effect at day 9. $E_2-induced$ stimulation of $[^3H]-thymidine$ incorporation was completely reversed by $E_2$ antagonists (progesterone or tamoxifen). $E_2$ ($10^{-9}\;M$) or EGF ($10^{-8}\;M$) significantly stimulated $[^3H]-thymidine$ incorporation by 144% and 154% of control. $E_2$ plus EGF was synergistic on $[^3H]-thymidine$ incorporation (204% of control), while $E_2$ plus IGF-I showed a slight but no significant synergistic effect. Cell number also displayed similar pattern. $E_2$ ($10^{-9}\;M$) significantly stimulated $P_i$ uptake to 134% of control. $E_2$-induced stimulation of $P_i$ uptake was partially reversed by $E_2$ antagonists. EGF or IGF-I ($10^{-8}\;M$) significantly also increased $P_i$ uptake to 132% or 129% of control. $E_2$ plus EGF had synergistic effect on $P_i$ uptake, while $E_2$ plus IGF-I did not. In conclusion, $E_2$ may act not only directly interaction with its receptors but also indirectly as a modulator of EGF in proliferation and $P_i$ uptake of primary cultured rabbit renal proximal tubular cells.