• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.628-634
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• 2016

This paper demonstrates a microfluidic electrochemical sensor for detecting endocrine disruptor such as estradiol at a very low concentration by using preconcentration technique. In addition, self-assembled monolayer(SAM) was also employed on the working electrode of the electrochemical sensor in order to increase the estradiol capture efficiency of the sensor. SAM treatment on the working electrode enhanced the specific binding between the surface of the working electrode and the estradiol antibody. The estradiol antibody was applied on the working electrode at different concentrations(10, 20, 50, 100, 200 pg/ml) for observing the concentration dependency. The measured electrochemical redox current changed with the amount of the bound estradiol on the Au working electrode surface and the sensor can detect all the target material when the immobilized antibody amount is more than the estradiol amount in the water. The elecrochemical estradiol sensor without SAM treatment showed a low current of 7.79 nA, while the sensor treated with SAM resulted in 339 nA at 200 pg/ml, which is more than 40 fold higher output current. When combining the preconcentration technique and the SAM-treated electrode, the measured current became more than 100 fold higher than that of the sensor without neither SAM treatment nor preconcentration technique. The combination of these two techniques can would enable the proposed microfluidic electrochemical sensor to detect a very low concentration endocrine disruptor.

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.109-116
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• 2009

Purpose: $17\beta$-estradiol is the most active endogenous estrogen, which is related to favorable changes in the plasma lipid profile, to relaxation of the coronary vessels, and to a decrease in platelet aggregation and vascular smooth muscle cell migration. However, although the beneficial effect of estrogens on plasma lipoproteins (ie, lowering low-density lipoprotein and increasing high-density lipoprotein cholesterol) contributes to cardiovascular protection, it does not fully account for the protective effect, particularly in the application of physical therapy, including low frequency electrical stimulation. Methods: The aim of this study was to demonstrate the inhibition of stressors, such as endothelin-1 (ET-1), serotonin (5-hydroxytryptamine, 5-HT), prostaglandin $F2\alpha$ ($PGF2\alpha$), and a protein kinase C (PKC) activator 12-deoxyphorbol 13-isobutyrate (DPB), induced isometric tension by $17\beta$-estradiol in vascular smooth muscle strips, respectively. In addition, the effects of low frequency electrical stimulation at the meridian points (CV-3, -4, Ki-12, SP-6, LR-3, BL-25, -28, -32, -52) on the indirect antihypertensive effect were examined by monitoring the changes in the serum $17\beta$-estradiol concentration in healthy volunteers. Results: Isometric tension analysis showed that the responses of inhibited tension by $17\beta$-estradiol were similar to the same stressors in rat aortic smooth muscle strips. Furthermore, although the continued amplitude modulation (AM) type of electrical stimulation was not increased significantly by electrical stimulation, the current of the frequency modulation (FM) type of low frequency electrical stimulation increased the serum $17\beta$-estradiol concentration in normal volunteers. Conclusion: These results, in part, suggest that $17\beta$-estradiol has the capacity to supress stressor-induced muscle tension, and electrical stimulation, particularly current of the FM type, has a modulatory effect on the sex steroid hormones, particularly $17\beta$-estradiol, in healthy volunteers.

• Korean Journal of Animal Reproduction
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• v.21 no.4
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• pp.363-371
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• 1997

The present study was carried out to investigate the effect of gonadotropin administration on blood ovarian steroid hormone in angora rabbit. Mature angora rabbits were primed for superovulation with PMSG 100IU. Eighty hours later, the rabbit were induced to ovulate with HCG 100IU. In exp 1, blood progesterone and estradiol of superovulated does were measured by radiommunoassay. Blood progesterone concentration at 93, 99, 102 and 114 hours after HCG injection were 12.9$\pm$0.5, 34.8$\pm$5.1, 12.2$\pm$2.7 and 43.4$\pm$5.8ng/ml, respectively. Mean progesterone concentration of blood collected at 99 and 114 hours after HCG injection(p<0.05). However, mean blood estradiol concentration was not changed. In exp 2, superovulated does were unilaterally ovariectomized at 96 hours after HCG injection. Blood progesterone concentration was tend to be decreased after ovariectomy. Nosignificant changes in blood estradiol concentration was observed after ovariectomy. In exp 3, superovulated does were bilaterally ovariectomized at 96 hours after HCG injection Ovariectomized does were treated with progesterone. Blood progesterone level in the rabbits treated, twice daily, with 5mg progesterone after ovariectomy was similiar to that in the superovulated intact rabbits. Blood estradiol concentration of the rabbits after bilateral ovariectomy was beyond detection range. Blood progesterone concentration was significantly decreased to 7.6$\pm$3.0ng/ml wi thin 3 hours after ovriectomy(p<0.05). However, that value was increased to 34.8$\pm$8.2ng/ml by 5 mg progesterone treatment and this elevated level was significatnly decreased to 7.3$\pm$2.4ng/ml at 12 hours after progesterone administration(p<0.05).

• The Korean Journal of Pharmacology
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• v.27 no.2
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• pp.183-189
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• 1991

The present study was performed to elucidate the factors which modulate uterine prostaglandin synthesis during the implantation period in rats, by employing delayed implantation model. Administration of estradiol sharply increased uterine cAMP concentration 4 hrs later during the delayed implantation process. Concentrations of uterine PGE and $PGF_2{\alpha}$ were increased at 12 hrs after the estradiol treatment although an increase in $PGF_2{\alpha}$ was not statistically significant. The concomitant treatment of indomethacin with estradiol significantly suppressed estradiol-induced PGE and $PGF_2{\alpha}$ at 12 hrs, while uterine cAMP concentration was not suppressed. The treatment of dbcAMP without estradiol gradually increased uterine PGE and $PGF_2{\alpha}$ showing the maximum 8 hrs later, suggesting that cAMP minics estradiol effect on uterine prostaglandin synthesis during the implantation process. Furthermore, the pretreatment of theophylline, phosphodiesterase inhibitor, induced significantly greater concentrations of uterine PGE and $PGF_2{\alpha}$, compared with estradiol-only treated group. These results suggest that estradiol stimulates uterine prostaglandin synthesis and this process may be mediated by an elevation of cAMP during the delayed implantation process in rats.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.1
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• pp.75-81
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• 1994

To elucidate the relationship between steroidogenesis and sex differentiation in the duck, plasma, testicular and ovarian testosterone, estradiol-$17{\beta}$ and progesterone concentration in male and female embryo of day 11 to 27 (just before hatching) of incubation and in 1- to 7-day-old male and female duckling were investigated by radioimmunoassays. Plasma estradiol-$17{\beta}$ concentration in female embryos declined from very high at days 11 and 15 of incubation and remained at low levels after hatching. Male plasma estradiol-$17{\beta}$ concentration were always lower than those of the female throughout this period. Plasma testosterone and progesterone concentrations in both sexes were low during the embryonic stage, but then increased to peaks 3 days and 1 day after hatching, respectively. Estradiol-$17{\beta}$ contents were much higher in the left ovary than the right ovary or testes throughout the experimental period. The estradiol-$17{\beta}$ content of the left ovary was very high at day 15 of incubation, and decreased gradually thereafter. Both in right ovary and testes, estradiol-$17{\beta}$ contents were always low. Testosterone and progesterone contents in the left ovary were low from day 11 to 23 of incubation, and reached a peak 1 day after hatching. Progesterone content in the right ovary and testes were low levels over time period examined. Testosterone and progesterone contents were much higher in the left ovary than the right ovary and testes. The present results clearly demonstrate that the capacity of the embryonic left ovary of duck to synthesize estradiol-$17{\beta}$ and testosterone is much higher than that of the embryonic testis. It is suggested that estrogen secreted from the embryonic ovary earlier than day 15 of incubation has an important role in female sexual differentiation in the duck, and the sex of the avian species is basically male with homozygous sex chromosome (ZZ).

• Korean Journal of Animal Reproduction
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• v.20 no.2
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• pp.135-141
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• 1996

Growth, mammary development, serum concentrations of growth hormone, prolactin and estradiol which affect the growth and mammary development, were investigated in Korean Native heifers and Holstein heifers from 5 months old to 15 months old. From 5 months old to 15 months old, body weights in Korean Native heifers averaged 37%, lower than those in Holstein heifers of the same age (P<.01). Teat volumes in Korean Native heifers are average 67% smaller than those in Holstein heifers. Analysis of serum protein by secondary electrophoresis showed differences in protein pattern between the breeds and between the individuals. From 5 months old to 15 months old, serum concentration of growth hormone in Korean Native heifers was averge 47% lower than that in Holstein (P<.01), yet prolactin concentrations in serum were about the same between the two breeds. However serum concentration of estradiol in Korean Native heifers was average 20% higher than that in Holstein of same age (P<.01). This result showed evidently that the decrease of the growth hormone concentration in serum, while growing up, causes to retard the growth and mammary development in Korean Native heifers compared to Holstein heifers.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.693-697
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• 2010

This study, conducted with four leopard cats (Prionailurus bengalensis), used time-resolved fluoroimmunoassay (TR-FIA) to analyze estradiol and progesterone concentrations in fecal samples. We measured fecal samples taken during estrus period, diestrus period, pregnancy and non-pregnancy period. During estrus (February), the mean minimum estradiol concentration was $4.02{\pm}1.9$ng/g, and the mean maximum was $86.01{\pm}35.2$ng/g (dry fecal weight). During diestrus (November), the mean minimum estradiol concentration was $4.42{\pm}1.32$ng/g and mean maximum was $15.62{\pm}6.48$ng/g (dry fecal weight). Midgestation (April), the mean minimum progesterone concentration was $427{\pm}24.49$ng/g and the mean maximum was $1490{\pm}265.27$ng/g. During non-pregnancy (November), the mean minimum progesterone concentration was $71.25{\pm}29.61$ng/g and the mean maximum was $291.75{\pm}90.30$ng/g. These results suggest that steroid hormone analysis of feces using TR-FIA is a valid method for noninvasively determining ovarian activity associated with estrus and pregnancy in leopard cats. This study will contribute to building breeding management and reproductive plans for endangered species.

• Journal of Embryo Transfer
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• v.3 no.1
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• pp.24-30
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• 1988

This study was conducted to investigate the effect of unilateral ovariectomy on the embryo survival and changes of plasma progesterone and estradiol concentration. Mature Angora rabbits were divided into 2 groups (Superovulation and unilateral ovariectomy after superovulation). Unilateral ovariectomied rabilts were subdivided into two groups according to the time of ovariectomy (24 hours and 96 hours after mating). The results obtained were summarized as follows; 1. After unilateral ovariectomy, survival rate and collecting rate of embryos recovered from contralateral and ipsilateral oviduct and uterus were not different, and were lower than intact rabbits. 2. Plasma progesterone concentration at 93, 99, 102 and 114 hours after HCG injection in superovulated rabbits were 12.9 $\pm$ 0.5, 34.8 $\pm$ 5.1, 12.2 $\pm$ 2.7 and 43.4 $\pm$ 5.8ng/ml, respectively. Mean progesterone concentrations were significantly higher at 99 and 114 hours than at 93 and 102 hours (p <0.05). But plasma estradiol concentration was not different. 3. Plasma progesterone concentration in unilateral ovariectomized rabbits was somewhat decreased after unilateral ovariectomy. Plasma estradiol concentration was not different.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2002.10a
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• pp.170-170
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• 2002

College of Pharmacy, Ewha womans University, Seoul, 120-750, Korea 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most potent halogenated aromatic hydrocarbon congener that induces expression of several genes including CYP1A1. Exposure to TCDD results in many toxic actions such as carcinogenesis, hepatotoxicity, immune suppression, and reproductive and developmental toxicity. Dramatic differences in dioxin toxicity have been observed between the sexes of some animal species, suggesting hormonal modulation of dioxin action. Many studies have been reported and propose several mechanisms of anti-estrogenic effects of TCDD. In contrast, the effect of estrogen on the regulation of CYP1A1 are not clear at present. There are several reports showing conflicting results. It seems that induction/inhibition of CYP1A1 may be dependent on cell-type and concentration. The purpose of this study was to investigate the regulation of TCDD-induced CYP1A1 gene expression by estradiol and its metabolites. We examined whether estradiol and its metabolites altered TCDD-mediated induction of CYP1A1 enzyme activity. 17 ${\beta}$ estradiol and 16 ${\alpha}$ estriol at non cytotoxic concentrations caused a significant concentration dependent decline of TCDD-induced EROD activity To determine whether reduced EROD activity reflected altered CYP1A1 mRNA expression, we measured CYP1A1 mRNA level by RT-PCR. And to examine whether estradiol and its metabolites have effects on TCDD-induced CYP1A1 gene expression at the transcription level, we also peformed transient transfection with an AhR responsive reporter plasmid containing the 5' flanking region of the human CYP1A1 gene to examine whether estradiol and its metabolites have effects on TCDD-induced CYP1A1 gene expression at the transcription level.

• Archives of Pharmacal Research
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• v.17 no.2
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• pp.109-114
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• 1994

The role of sex homones in hepatic lipid peroxidation, and in hepatic adehyde odidase and xanthine oxidase activites were investigated using rat liver homogenates. It was observed that male rt had a significantly greater content of malondialdehyde in liver than female. Among the sex hormones tested, estradiol, one of female hormones, markedly inhibited the formation of lipid peroxides in liver tissues in vitro. Especially, the inhibitory effect of estradiol appeared more remarkably in Fe-induced lipid peroxidation. The hepatic xanthine oxidase activity was decreased about 15% by $10\;^6\;M$ estradiol, wherease, the adehyde oxidase activity was almost completely disappeared at the same concentration of estradiol. It implies that sex differences in lipid peroxidation is attributed to the suppression of radical generating system by estradiol.