• Korean Journal of Veterinary Service
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• v.31 no.4
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• pp.457-463
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• 2008

The sex steroid hormone estradiol-$17{\beta}(E_2)$ mediate their biological effects on development, differentiation and maintenance of reproductive tract and other target tissue through gene regulation by nuclear steroid receptors. Although the importance of $E_2$ in many physiological process has been reported, but little is known about the effects of $E_2$ on primary cultured chicken hepatocyte. therefore, in the present study, we have examined the effect of $E_2$ on cell proliferation and it's related signal cascades. $E_2$ increase $[^3H]$-thymidine incorporation in time-(${\leq}8hr$) and dose-($10^{-10}M$)dependent manner and treatment of $E_2$ increased the phosphorylation of p44/43 MAPKs(p44/42 mitogen-activated protein kinase) and JNK(c-Jun N-terminal kinase) in a time dependent manner. In addition, PD98059(p44/42 blocker, $10^{-5}M$), SP600125(JNK blocker, $10^{-6}M$) blocked the estrogen-induced increase in $[^3H]$-thymidine incorporation. In conclusion, $E_2$ stimulates the proliferation of primary cultured chicken hepatocytes and this action is mediated by p44/42 MAPKs and JNK signal transduction pathway.

• Journal of Veterinary Clinics
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• v.31 no.1
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• pp.25-30
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• 2014

This study tested the hypothesis that the priming effects of progesterone on the timing of the LH surge induced by exogenous estradiol are more potentiated the negative feedback actions of progesterone on LH secretion by the existence of estradiol. In previous studies, the time interval from estradiol infusion until the peak of LH surge was gradually and significantly extended by the different levels of progesterone treated before estradiol infusions. Longterm ovariectomized Shiba goats that had received implants of estradiol capsules (Day 0) and three different progesterone silastic packet inducing follicular, subluteal and luteal levels of progesterone were divided into three groups such as non-P, low-P and high-P group. Blood samples were collected daily throughout the experiment for the analysis of gonadal steroid hormone levels. On Day 7, all devices of progesterone and estradiol packets were removed but estradiol capsules were maintained during the experiment, and blood samples were collected at 1 hr interval for 12 h from the time of progesterone removals to determine peripheral changes of estradiol and progesterone concentration. Then all animals were infused estradiol on the Day 7 after 13 h from the removals of progesterone devices with a peristaltic pump into jugular vein at a rate of 3-6 ${\mu}g/h$ for 36 h. For analysis of peripheral LH and estradiol concentration, blood samples were collected via another jugular vein at 2 h intervals for 52 h (from 4 h before the start of estradiol infusion to 48 h after the start of estradiol infusion). In all animals of the three groups treated with estradiol infusion, an LH surge was expressed but the peak time of LH surge was different. This time interval was not extended by the different levels of progesterone treated before estradiol infusions and the difference was not significant during this interval between the Low P and the High P groups. Progesterone pretreatment may contribute to regulating the neural system that is responded by estradiol, and estradiol existence potentiates the negative feedback effect of progesterone on GnRH/LH surge-generating system.

• Biomedical Science Letters
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• v.19 no.2
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• pp.147-152
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• 2013

17-${\beta}$-hydroxysteroid dehydrogenase type 1 ($17{\beta}$-HSD type 1) mediates the reaction of $17{\beta}$-estradiol (E2) production from estrone (E1). Inhibitory effects of curcuminoids on $17{\beta}$-HSD type 1 activity were investigated to find a lead compound for treating estrogen-dependent diseases including breast cancer. Among curcuminoids, demethoxycurcumin showed potent inhibitory effect ($IC_{50}=2.7{\mu}M$) on mouse $17{\beta}$-HSD type 1. Curcuminoids also displayed their inhibitory effects on the production of $17{\alpha}$-estradiol which is a carcinogenic metabolite produced by the enzyme. Bisdemethoxycurcumin ($IC_{50}=1.3{\mu}M$) showed potent inhibitory effect on the $17{\alpha}$-estradiol production by chicken $17{\beta}$-HSD type 1. Curcuminoids did not inhibit ERE transcriptional activity with and without E2. Taken together, curcuminoids can be used for treating and preventing E2-dependent diseases via inhibition on $17{\beta}$-HSD type 1 activity.

• Korean Journal of Animal Reproduction
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• v.16 no.4
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• pp.325-333
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• 1993

A competitive type immunoassay method for 17$\beta$-estradiol(E2) based on the idiotypic anti-idiotypic antibody and time-resolved fluorescence is described. The anti-idiotypic antibody(Ab2) produced to E2 binding site of the primary idiotype antibody (Ab1) was labelled with europium and was allowed to compete with E2 standards or serum sample for the binding sites of Ab1 which was bound to 2nd antibody captured ontothe surface of microtitre plates. Fluorescence measured by time-resolved fluorometer was inversely proportional to the concentration of E2 over the range 5~500pg/well. The sensitivity of the assay was 5pg per well which was compatible with that ofradioimmunoassay using the same Ab1 and 3H-E2 as a tracer. One great advantage of this method described here was to enable antibodies to be labelled instead of haptens, and thus makes it easier to develop sensitive and robust immunoassay systems specially for haptens.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.62-67
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• 2019

We studied the effect of several sex-related steroid hormones (serotonin, progesterone and ${\beta}$-estradiol) for 6 days on the induction of sexual reproduction for the mass production of resting eggs in the marine rotifer Brachionus rotundiformis. The highest mix rate of 20.6% appeared with the ${\beta}$-estradiol ($E_2$) treatment on the third day. The number of resting eggs was highest with $E_2$ treatment, followed by that of the serotonin treatment group. In addition, we investigated the effect of the hormones on the expression pattern of the genes related to sexual reproduction in the rotifer. NrbP, SRY, Cyclin and MrpmB genes were up-regulated with all the hormone treatments. As a result, ${\beta}$-estradiol was more effective than the other hormone treatments to produce resting eggs in B. rotundiformis. We suggest that the sexual reproduction-related genes in the rotifer are the NrbP, SRY, Cyclin and MrpmB genes. Further study is required to determine the optimum concentration of $E_2$ for the effective production of resting eggs in the rotifer.

• Environmental Analysis Health and Toxicology
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• v.16 no.1
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• pp.21-28
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• 2001

A common used endpoint in bioassays testing the estrogenicity of chemicals including endocrine disruptors is the induction of egg yolk Precursor vitellogenin in male fish. Two marine fishes (Sebastes schlegeli and Paralichthys olivaceus) were exposed to the 17$\beta$-estradiol(E2) to determine the vitellogenin production. Vitellogenin was measured in fish blood using SDS-PAGE and Densimetry. Results showed that exposure to E2 caused vitellogenin in male fish. Especially, vitellogenin levels in young fish were about 4 times higher than in adult fish, which means young fish are more sensitive to E2 exposure. And plasma vitellogenin in fish increased related to E2 concentration and exposure duration.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.897-900
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• 2000

The experiment was conducted to study the effect of GnRH administration at induced estrus on pituitary and ovarian response in buffalo heifers. Eight Murrah river buffaloes of 12 to 13 months of age were treated with $PGF_{{2}{\alpha}}$ and eCG combination. GnRH (Fertagyl) 200 ug was injected (iv) at estrus in four heifers (treated group) while saline (2 ml, iv) was injected in remaining four heifers (control group). Blood was collected through jugular catheter to estimate plasma FSH, LH and estradiol level. The pretreatment plasma FSH, LH and estradiol values ranged from $8.46{\pm}1.97ng/ml$ to $12.31{\pm}1.30ng/ml$, $0.87{\pm}0.21ng/ml$ to $1.19{\pm}0.29ng/ml$ and $19.09{\pm}2.38pg/ml$ to $20.24{\pm}1.00pg/ml$ respectively. The plasma estradiol concentration elevated significantly (p<0.05) within 24 hr after eCG administration and reached its peak levels of $154.09{\pm}17.28pg/ml$ and $181.95{\pm}31.82pg/ml$ at estrus in respectively treatment and control groups. The plasma FSH and LH concentrations did not increase during follicular development after eCG administration while initial significant (p<0.05) increases in both plasma FSH and LH concentrations occured within 5 and 10 min, reaching peak levels of respectively $110.06{\pm}23.56ng/ml$ and $13.15{\pm}3.13ng/ml$ within 90 min after GnRH injection was detected. A sharp and significant decline in plasma estradiol concentration ($59.27{\pm}8.78pg/ml$) associated with synchronized ovulation within 24 hours after GnRH injection was recorded. The observation suggest that the hypophysis of prepubertal buffaloes treated with eCG have gonadotrophins awaiting the releasing factor to evoke release of gonadotrophin during the follicular phase to induce synchronized ovulation.

• Journal of Life Science
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• v.23 no.8
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• pp.998-1003
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• 2013

The effects of oral administration of estradiol-$17{\beta}$ (E2) on glass eels (Body weight: $0.16{\pm}0.05g$, Total length: $6.2{\pm}0.9cm$) and young eels (Body weight: $2.6{\pm}0.6g$, Total length: $13.2{\pm}0.6cm$) on gonadal sex and growth were examined, respectively. Glass eels were fed a diet containing E2 at a dose of 10 mg/kg or 25 mg/kg, respectively, for five months. The female ratio significantly increased in all E2-treated groups (10 mg/kg diet group: 70%; 25 mg/kg diet group: 90%) when compared to the control group (10%). Young eels were fed a diet containing E2 at a dose of 25 mg/kg for four months. The female ratio also significantly increased in the E2-treated groups (60%) compared to the control group (20%). The highest female ratio was observed in the stage of glass eels rather than young eels. In all experiments, however, the growth of eels treated with E2 was similar to that of controls to the end of the experiment. Thus, oral administration of E2 could be a good approach to controlling sex differentiation.

• Journal of fish pathology
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• v.17 no.3
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• pp.191-198
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• 2004

Temporal changes of plasma vitellogenin (VTG), alkaline-labile protein phosphorus (ALPP), calcium (Ca), glutamate pyruvate transaminase (GPT) and hepatosomatic index (HSI) were examined in the $estradiol-17\beta$ ${E_2}$-administered immature rockfish, Sebastes schlegeli. Fish were intraperitoneally injected with ${E_2}$ (5 ㎎/kg B.W.) in 70% ethanol and then plasma were extracted at 0, 1, 3, 6, 9, 12 and 15 days. VTG band was detected at a molecular weight position of about 170 kDa on Day 3 in SDS-PAGE. This band became more distinct at 6 days but its was gradually thinned with time-course, and not detected at 15 days. Plasma ALPP and Ca increased suddenly at 1 day and the highest concentrations were detected at 6 days and then these concentrations decreased gradually with time-course. ALPP and Ca concentrations at 15 days after E2 administration were very similar to that before E2 administration. GPT was increased at 1 day and higher GPT was detected at 3 days. However, GPT was gradually decreased with time-course. GPT and HSI at 15 days after E2 administration were also very similar to that before E2 administration. HSI was also increased at 1 day and the highest value was detected at 3 days and then gradually decreased with time-course. These results suggest that plasma ALPP, Ca, GPT and HSI could be utilized as a biomarker of exogenous E2 exposure in coastal ecosystem, because the changes of ALPP, Ca, GPT and HSI after E2 administration are very similar to that of VTG.

• Biomolecules & Therapeutics
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• v.17 no.2
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• pp.188-198
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• 2009

This work was conducted to investigate the effect of bisphenol A (BPA) on estradiol (E2) 2-and 4-hydroxylase activities in the liver, kidney and lung tissues of male and female rats. After intraperitoneal administration of BPA to male and female rats for 4 days at 0, 10, and 50 mg/kg, the conversion of the substrate for hepatic and extra-hepatic enzyme activities was measured by GC/MSD. The result showed decreases of body and organ weights at 50 mg/kg BPA of male and female rats. Male hepatic E2 2-hydroxylase activity was inhibited by 68% at 10 mg/kg and by 82% at 50 mg/kg BPA. Female hepatic E2 2-hydroxylase activity was decreased by 46% at 10 mg/kg and by 56% at 50 mg/kg to the control. E2 4-hydroxylase was inhibited by 57 and 57% at 10 mg/kg and 54 and 78% at 50 mg/kg in liver of female and male, respectively. The urinary excretion rate of 2-hydroxyestradiol (2-OHE), androsterone and testosterone in urine of female rats with 50 mg/kg BPA were decreased significantly. The results showed that 50 mg/kg BPA was decreased E2 2-and 4-hydroxylase activities in liver, but not in other tissues. The urinary excretion rates of 2-OHE, androsterone and testosterone were also decreased. In liver, estrogenic enzyme activity were higher in male than female. These results suggest that BPA can disrupt estrogen metabolism by suppressing E2 2-and 4-hydroxylase activities in the liver of male and female rats.