• 대한수의학회지
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• 제38권3호
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• pp.508-517
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• 1998

There is evidence that the sympathetic nervous system exerts a control on thyroid function via an adrenergic innervation of thyroid cells. Although it is clear that the inhibitory effects of catecholamines result from an activation of ${\alpha}_1$-adrenoceptors, the mechanisms involved in ${\alpha}_1$-stimulation are not fully understood. The effects of methoxamine and protein kinase C (PKC) activator on the release of thyroxine ($T_4$) from mouse thyroid were studied to clarify the role of PKC in the regulation of $T_4$ release in vitro. The glands were incubated in the medium, samples of the medium were assayed for $T_4$ by EIA kits. Methoxamine inhibited the TSH-stimulated $T_4$ release. This inhibition was reversed by prazosin, an ${\alpha}_1$-adrenergic antagonist. Futhermore, the inhibitory effect of methoxamine on the $T_4$ release stimulated by TSH was prevented by chloroethylclonidine, an ${\alpha}_{1b}$-adrenoceptor antagonist, but not by WB4101, an ${\alpha}_{1a}$-adrenoceptor antagonist. Also methoxamine inhibited the forskolin-, cAMP- or IBMX-stimulated $T_4$ release. These inhibition were reversed by PKC inhibitors, such as staurosporine and $H_7$. PMA, a PKC activator, completely inhibited the TSH-stimulated $T_4$ release, and its inhibition was reversed by staurosporine and $H_7$, but not by chelerythrine. R59022 (a diacylglycerol kinase inhibitor), like methoxamine, also inhibited the TSH-stimulated $T_4$ release, and its inhibition was also reversed by staurosporine. The present study suggests that methoxamine inhibition of $T_4$ release from mouse thyroid can be induced by activation of the ${\alpha}_{1b}$-adrenoceptors and that it is mediated through the ${\alpha}_1$-adrenoceptor-stimulated PKC formation.

• 대한수의학회지
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• 제39권6호
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• pp.1073-1080
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• 1999

Previous studies suggested that the inhibition of thyroxine ($T_4$) release by ${\alpha}_1$-adrenoceptor and muscarinic receptor stimulation results in activated protein kinase C (PKC) from mouse and guinea pig thyroids. In the present study, the effect of carbachol, methoxamine, phorbol myristate acetate (PMA), and R59022 on the release of $T_4$ from the mouse, rat, and guinea pig thyroids was compared to clarify the role of PKC in the regulation of the release of $T_4$. The thyroids were incubated in the medium containing the test agents, samples of the medium were assayed for $T_4$ by EIA kits. Forskolin, an adenylate cyclase activator, chlorophenylthio-cAMP sodium, a membrane permeable analog of cAMP, and isobutyl-methylxanthine, a phosphodiesterase inhibitor, like TSH (thyroid stimulating hormone), enhaced the release of $T_4$ from the mouse, rat, and guinea pig thyroids. Methoxamine, an ${\alpha}_1$-adrenoceptor agonist, inhibited the TSH-stimulated release of $T_4$ in mouse, but not rat and guinea pig thyroids. In contrast, carbachol, a muscarinic receptor agonist, inhibited the release of $T_4$ in guinea pig, but not mouse and rat thyroids. These inhibition were reversed by prazosin, an ${\alpha}_1$-adrenoceptor antagonist or atropine, a muscarinic antagonist or $M_1$- and $M_3$-muscarinic antagonists, in mouse or guinea pig thyroids. In addition, staurosporine, a PKC inhibitor, reversed methoxamine or carbachol inhibition of TSH stimulation. Furthermore, PMA, a PKC activator, and R59022, a diacylglycerol (DAG) kinase inhibitor, inhibited the TSH-stimulated release of $T_4$ in mouse, rat, and guinea pig thyroids. These inhibition were blocked by staurosporine. These findings suggest that the activation of receptor or DAG inhibits TSH-stimulated $T_4$ release through a PKC-dependent mechanism in thyroid gland.

• 대한핵의학회지
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• 제7권2호
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• pp.1-12
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• 1973

The most commonly used methods for determining thyroxine binding globulin(TBG) concentration as the total thyroxine-binding capacity utilize electrophoretic seperation of serum. Although technically simple, the electrophoretic method is time consuming and is limited in the number of samples which can be run in a single assay. The author presented a single $T_4$ load ion exchange resin method as an approach to simplify the technique as with clinical practicability and results were analyzed. For construction of the standard curves, serum mixtures were diluted with barbital buffer.which effectively blocked $T_4$-binding to TBPA. For each serum dilution, a constant amount of $T_4-^{125}I$ and increments of unlabelled $T_4$ were added. After incubation in water bath, resin beads were dispensed to the samples which binded all $T_4$ not bound to TBG. The radioactivity in the supernatant was counted in the gamma scintillation counter. Each standard curve was plotted from the percent counts in the supernatant and total $T_4$ in each tube. Unknown samples were diluted to 1:40 and ran at a single $T_4$ loading concentration, and the TBG capacity of the samples was able to be read on the standard isobars. The following results were obtained. 1) Mean and standard deviation for TBG capacity in normal population was $28.6{\pm}5.09{\mu}g\;T_4/100ml$. 2) $24.9{\pm}3.87{\mu}g\;T_4/100ml$ in hyperthyroidism showed low TBG capacity comparing to normal population.(p<0.025) 3) $31.0{\pm}2.40{\mu}g\;T_4/100ml$ in hypothyroidism showed high TBG capacity tendency comparing to normal population. 4) Reversed correlationship existed between TBG capacity and $T_3$ resin uptake(r=-0.624), TBG capacity and serum $T_4$ value (r=-0.859), and TBG capacity and free thyroxine index(r=-0.623). The author assumes that this method of assay is considerably simpler in instrumentation and technique than any other assays traditionally being used, and seems to be more practical for routine clinical laboratory use.

• Clinical and Experimental Pediatrics
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• 제45권6호
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• pp.796-799
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• 2002

티록신 결합글로불린 결핍증은 대부분 갑상선기능저하증을 동반하지 않으므로 갑상선 호르몬 보충 요법이 필요 없으나 드문 예에서 유리 티록신 농도가 정상치 보다 낮게 유지되고, 중추 신경계에 대한 갑상선 호르몬의 부족에 의해 갑상선 자극호르몬이 정상치 보다 증가하는 경우가 있다. 이런 경우는 티록신 결합글로불린의 결핍 정도가 갑상선기능저하증을 유발할 수 있을 정도로 갑상선 호르몬의 이동과 갑상선 밖의 호르몬 저장에 영향을 주는 것이므로 갑상선호르몬의 보충요법이 필요하게 된다. 저자들은 갑상선기능저하증을 동반하여 갑상선 호르몬의 투여가 필요한 중증의 티록신 결합글로불린 결핍증 1례를 보고하는 바이다.

• 대한한방내과학회지
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• 제21권3호
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• pp.399-407
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• 2000

This study was carried out to examine if Haejohwan (HJ) inhibits oxidant-induced lipid peroxidation and therby produces protective effect against thyroxine-induced hyperthyroid rats. Triiodothyronine $(T_3)$, thyroxine $(T_4)$, lipid peroxidation, xathine oxidase activities and type conversion ratio were increased in thyroxine treated group. However, they were decreased in HJ extract's pre-applied group. Glutathione level, activities of glutathione peroxidase, glutathione Stransferase and glutathione reductase were decreased in thyroxine treated group. But, they were increased in HJ extract's pre-applied group. These results suggest that in thyroxine-induced hyperthyroid rats HJhas an increase in the activities of oxygen free radical scavenging enzymes and inhibition of xanthine oxidase activities, and prevents lipid peroxidation.

• 한국가축번식학회지
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• 제11권1호
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• pp.16-21
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• 1987

We describe a simple, solid-phase chemiluminescence immunoassay for the meausrement of serum T4. An immunoglobulin G fraction of antibody to thyroxine was passively absorbed onto the walls of polystyrene tubes. The labeled antigen was thyroxine-aminobutylethylisoluminol. After the bindings reaction (37$^{\circ}C$ for 1 hour), the solution is removed by aspiration and the antibody-bound fraction was washed once with buffer. Sodium hydroxide (5mol/1,200${mu}ell$) was added and the mixture incubated for 30 minutes at 6$0^{\circ}C$. Luminescence was initiated by oxidation of the label with micropeeroxidase-hydrogen peroxide and the signal of light emission was intergrated for 10 sec. The light yield was inversely proportional to the concentration of T4 in the standard or sample. An evaluation of the method gave the following values sensitivity of calibration curve 7.5$\pm$2.8 nmol/l (mean$\pm$SD). The intra-assay precision (CV%) was 8.9, 7.3 and 5.4. The inter-assay precision (CV%) was 10.2, 8.1 and 7.1. When seum samples were assayed for T4, the results obtained by solid-phase CIA and the conventional RIA agreed well(n=3.5, r=0.954).

• 한국식품영양과학회지
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• 제26권3호
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• pp.507-513
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• 1997

This study was carried out to examine whether kimchi has hypolipidemic effect and to know how it exert lipid-lowering effect in rats. Male Sprague-Dawley rats were fed with kimchi-fee diet, or 3%, or 5%, or 10% kimchi diets for 6 weeks. Plasma cholesterol level was lowered in rats fed all concentrations of kimchi diets, and plasma triglyceride(TG) level was lowered in 10% kimchi diet group compared with that of control significantly(p<0.05). Th intake of kimchi lowered VLDL-cholesterol and VLDL-TG levels, whereas increased HDL-cholesterol level significantly(p<0.05). LDL-cholesterol level was lowered only in 5% kimchi diet group and LDL-TG level was lowered in all kimchi diet groups compared with those of control significantly (p<0.05). the intake of 5% and 10% kimchi diets also lowered the levels of hepatic cholesterol, TG, total lipid, and apolipoprotein B, whereas increased the levels of fecal total fat, cholesterol, TG, and apolipoprotein A-1 significantly(p<0.05). Triiodothyronine(T$_3$) level was elevated in rats fed kimchi diet, whereas thyroxine(T$_4$) level was not affected by kimchi treatment. These observations support that the intake of kimchin in rats loweres plasma and hepatic lipid levels by increasing the excretion of TG and cholesterol through feces, by the elevation of T$_3$ level, and by the altered lipoprotein metabolism.

• Clinical and Experimental Pediatrics
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• 제49권6호
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• pp.677-685
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• 2006

목 적 : 임신 기간 중 지속적으로 알코올을 섭취하는 모체에 thyroxine을 투여하여 알코올의 유해한 영향으로 인한 대뇌의 태아 알코올 효과를 개선시킬 수 있는지를 알아보고자 했다. 방 법 : 실험동물은 매일 35칼로리 정도의 알코올을 섭취한 알코올군, 알코올 대신 dextrin이 첨가된 유동액을 섭취한 정상군, 알코올군과 같은 양의 알코올을 매일 섭취하고 thyroxine을 매일 $5{\mu}g/kg$ 피하 주사한 알코올＋$T_4$ 군으로 분류하였다. 임신한 흰쥐 모체가 분만이 끝나면 각 군에서 태어난 새끼들은 그 어미와 분리하여 사료와 물을 자유롭게 섭취하는 대리모에게 키우게 하였다. 한 배의 새끼 1마리씩 총 4마리를 생후 0, 7, 14, 21, 28일에 희생시켜 면역조직화학염색을 시행하여 대뇌겉질 및 해마에서 생후 연령에 따른 NPY 함유 신경세포의 발달과 성숙양상을 관찰하였다. 결 과 : 대뇌겉질에서는 알코올＋$T_4$ 군에서 생후 7일에 NPY 함유 신경세포들이 알코올군과 정상군보다 더 뚜렷한 양성반응을 나타내기 시작하였으며, 생후 14일 이후부터는 대뇌겉질의 전 층에 걸쳐 광범위하게 NPY 함유 신경세포들이 관찰되었고 연령 증가에 따른 세포의 감소가 나타나지 않았으나 알코올군은 NPY 함유 신경세포가 생후 28일에 다른 군에 비해 현저히 감소하는 양상을 나타냈다. 해마에서는 알코올＋$T_4$ 군에서 생후 7일부터 정상군과 유사한 분포 양상을 나타냈으며 알코올군과는 뚜렷한 차이를 보였다. 특히 생후 14일에 대뇌겉질 및 해마 모두에서 알코올＋$T_4$ 군의 NPY 함유 신경세포 분포 및 신경얼기 형성이 두드러졌다. 결 론 : 임신 중 알코올 남용을 하는 모체에 지속적인 $T_4$ 투여는 그 후손들의 뇌에 분포하는 NPY 함유 신경세포의 발달을 정상 군과 유사하게 촉진시킬 수 있을 것으로 생각되며 모체 $T_4$ 투여가 특히 출생 초기의 NPY 합성에 영향을 미쳐 태아 알코올 효과를 개선시킬 수 있을 것으로 생각된다.

• 대한수의학회지
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• 제38권4호
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• pp.712-719
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• 1998

Thyroid function is mainly regulated through cAMP and phophatidylinositol, and it is well known that TSH-stimulated thyroxine ($T_4$) release is inhibited by catecholamine from mouse thyroids via the ${\alpha}_1$-adrenoceptor stimulation. Previous study has established that the inhibition of $T_4$ release by ${\alpha}_1$-adrenoceptor stimulation results in activated protein kinase C (PKC). The purpose of this study was to determine if ion transport systems are involved in the inhibition of $T_4$ release elicited by ${\alpha}_1$-adrenergic agonist in mouse thyroids. TSH-, IBMX- and cAMP analogue-stimulated $T_4$ release were significantly inhibited by methoxamine, R59022 (diacylglycerol kinase inhibitor), and MDL (adenylate cyclase inhibitor). TSH-stimulated $T_4$ release could be inhibited by Bay K 8644 and cyclopiazoic acid, but not by verapamil and tetrodotoxin. The addition of nifedipine ($Ca^{2+}$ channel blocker), tetrodotoxin and lidocaine ($Na^+$ channel blockers), but not amiloride (EIPA) and ryanodine, completely blocked the inhibitory effects of methoxamine on $T_4$ release. TSH-stimulated $T_4$ release was also inhibited by benzamil ($Na^+-Ca^{2+}$ exchange inhibitor). TSH-, IBMX- and cAMP-stimulated $T_4$ release were inhibited by methoxamine or R59022, these effects were reversed by nifedipine. but not by verapamil. Furthermore, nifedipine reversed the inhibitory effects of benzamil and R59022 on TSH-stimulated $T_4$ release. These data suggest that the observed ${\alpha}_1$-adrenoceptor-mediated inhibition of $T_4$ release in mouse thyroids is the result of an increase in intracellular $Na^+$ or $Ca^{2+}$ effected via activation of fast $Na^+$ or nifedipine-sensitive $Ca^{2+}$ channels, and that $Na^+-Ca^{2+}$ exchange may play an important role in reducing thyroid hormone by increasing intracellular $Ca^{2+}$.

• 한국가축번식학회지
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• 제16권4호
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• pp.353-361
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• 1993

This study was taken to examine external changes, behavioral changes, and endocrine changes such as estradiol-17$\beta$, progesterone, T4 and T3 of female Oreochromis niloticus living in 0$\textperthousand$, 10$\textperthousand$, 20$\textperthousand$, and 30$\textperthousand$ salt concentrations, respectively. The results obtained in these experiments were summarized as follows. In seawater obtained in these experiments were summarized as follows. In seawater challenge test, any fish didn't die in each group such as 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$. When fish were adapted from 0$\textperthousand$ to 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$, external body color of fish changed from dark-striped to light-grey color. At the same time, thyroxine and triiodothyronine concentrations significantly(P<0.05) increased, and then were at the highest level in 30 salinity. When fish were adapted from 0$\textperthousand$ to 10$\textperthousand$, feed intake of fish started from the fourth day. From 0$\textperthousand$ to 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$, estradiol-17$\beta$ levels were increased gradually. When fish was adapted from 0$\textperthousand$ to 10$\textperthousand$, 20$\textperthousand$ and 30$\textperthousand$, the levels of each progesterone didn't show significant change, and especially showed the lowest peak in 20$\textperthousand$. The greatest thyroxine activity(T4) was observed in 30$\textperthousand$. The levels of and triiodothyronine(T3) significantly changed in all salinities, and its level was at the highest peak in 30$\textperthousand$ salinity. Correlation coefficients between serum progesterone and triiodothyronine in 10$\textperthousand$ and 30$\textperthousand$ were ＋0.677 and ＋0.843, respectively. Correlation coefficient of serum thyroxine(T4) and triiodothyronine(T3) individuals in 10$\textperthousand$ was ＋0.768, and ＋0.843, respectively.