• The Korean Journal of Physiology
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• 제29권2호
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• pp.191-202
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• 1995

The purpose of this study was to compare effects of insulin and IGFs on growth, apical membrane enzyme activities and membrane transport systems of primary cultured rabbit kidney proximal tubule cells. Results were as follows: 1. Insulin and IGF-I produced significant growth stimulatory effects at $5{\times}10^{-10}M.\;IGF-II(5×10^{-10}\;M)$ did not stimulate significant cell growth. 2. Insulin stimulated the phosphorylation of a 97 KD protein. It was difficult to determine whether this band represents insulin and/or the IGF-I receptor. 3. The activities of apical membrane enzymes (alkaline phosphatase, leucine aminopeptidase, and ${\gamma}-glutamyl \;transpeptidase)$ were observed to be diminished after the cells were placed in the culture environment. 4. The uptake of ${\alpha}-MG,$ Pi and Na was significantly increased in cells incubated with insulin or IGF-I, IGF-II had no effect on the uptake of these substrates. 5. Na-pump activity, as assayed by Rb uptake, was significantly increased in cells treated with insulin or IGFs. In conclusion, insulin and IGF-I exert stimulatory effects on growth and membrane transporter(glucose, Na, Pi, and Na-pump) activities in primary cultured rabbit kidney proximal tubule cells. IGF-II had no effect on cell growth and membrane transporter(glucose, Na and Pi) activities.

• BMB Reports
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• 제39권4호
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• pp.383-393
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• 2006

Little is known concerning the mechanisms responsible for the transplacental transfer of thiamine. So, the aim of this work was to characterize the placental uptake of thiamine from the maternal circulation, by determining the characteristics of $^3H$-thiamine uptake by a human trophoblast cell line (BeWo). Uptake of $^3H$-thiamine (50-100 nM) by BeWo cells was: 1) temperature-dependent and energy-independent; 2) pH-dependent (uptake increased as the extracellular medium pH decreased); 3) $Na^+$-dependent and $Cl^-$-independent; 4) not inhibited by the thiamine structural analogs amprolium, oxythiamine and thiamine pyrophosphate; 5) inhibited by the unrelated organic cations guanidine, N-methylnicotinamide, tetraethylammonium, clonidine and cimetidine; 6) inhibited by the organic cation serotonin, and by two selective inhibitors of the serotonin plasmalemmal transporter (hSERT), fluoxetine and desipramine. We conclude that $^3H$-thiamine uptake by BeWo cells seems to occur through a process distinct from thiamine transporter-1 (hThTr-1) and thiamine transporter-2 (hThTr-2). Rather, it seems to involve hSERT. Moreover, chronic (48 h) exposure of cells to caffeine ($1\;{\mu}M$) stimulated and chronic exposure to xanthohumol and iso-xanthohumol (1 and $0.1\;{\mu}M$, respectively) inhibited $^3H$-thiamine uptake, these effects being not mediated through modulation of the expression levels of either hThTr-1 or hSERT mRNA.

• 한국작물학회지
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• 제51권4호
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• pp.295-297
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• 2006

Potassium (K) distribution in rice (Oryza sativa L.) root was studied by confocal laser microscopy, using potassium sensitive fluorescent dye potassium-binding benzofuran isophthalate (PBFI). Significantly high intensity of K-specific fluorescence was detected at the root cap region followed by meristematic and basal regions. A negligible or fainted fluorescence was observed at the root hairs area. These results suggest that K is heavily distributed in the apical area of rice root, which may be required in higher concentration for division and extension of cells, as it is the rapidly growing region of the root, moreover, may also be involved in water uptake by creating osmotic gradient across membranes.

• Archives of Pharmacal Research
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• 제29권4호
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• pp.318-322
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• 2006

Many quaternary ammonium salts are incompletely absorbed after their oral administration and may also be actively secreted into the intestine. However, the underlying mechanism(s) that control the transport of these cations across the intestinal epithelium is not well understood. In this study, the mechanism of absorption of quaternary ammonium salts was investigated using Caco-2 cell monolayers, a human colon carcinoma cell line. Tributylmethylammonium (TBuMA) was used as a model quaternary ammonium salts. When TBuMA was administrated at a dose of 13.3 imole/kg via iv and oral routes, the AUC values were $783.7{\pm}43.6\;and\;249.1{\pm}28.0{\mu}mole\;min/L$ for iv and oral administration, indicating a lower oral bioavailability of TBuMA $(35.6\%)$. The apparent permeability across Caco-2 monolayers from the basal to the apical side was 1.3 times (p<0.05) greater than that from the apical to the basal side, indicating a net secretion of TBuMA in the intestine. This secretion appeared to be responsible for the low oral bioavailability of the compound, probably mediated by p-gp (p-glycoprotein) located in the apical membrane. In addition, the uptake of TBuMA by the apical membrane showed a $Na^+$ dependency. Thus, TBuMA appears to absorbed via a $Na^+$ dependent carrier and is then secreted via p-gp related carriers.

• Journal of Applied Biological Chemistry
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• 제51권3호
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• pp.102-110
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• 2008

Complementation assay of the urea uptake-defective yeast mutants led to the identification of the Arabidopsis AtTIP4;1 gene encoding the aquaporin. However, its physiological functions still remain elusive. In the present study, histochemical and genetic analyses were performed to understand the physiological roles of AtTIP4;1 in urea uptake. The AtTIP4;1 product was detectible in the roots, but not in the leaves, the stem, and the flower. Its promoter allowed the expression of the $\beta$-glucuronidase reporter gene in the roots and the apical meristem in Arabidopsis. The AtTIP4;1 products were induced under nitrogen-deficient conditions. To investigate the role of the tonoplast intrinsic protein in urea transport and developments, Arabidopsis with the loss- and the gain-of-function mutations by T-DNA insertion in AtTIP4;1 and 35S promoter-mediated overexpression of AtTIP4;1 were identified, respectively. The transfer DNA insertion and the AtTIP4;1-overexpressed plants showed normal growth and development under normal or abiotic stress growth conditions. The urea-uptake studies using $^{14}C$-labeled urea revealed higher accumulation of urea in the AtTIP4;1-overexpressed plants. These results provide evidence that overexpression of AtTIP4;1 leads to the increase in the urea-uptake rate in plants without detectable defects to the growth and development.

• Applied Microscopy
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• 제23권1호
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• pp.1-14
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• 1993

본 연구는 세포질 액포의 수와 기능적으로 상호작용하는 정단세포막(丁端細胞膜)의 역동적(力動的) 변화로 인한 세포수송의 조절과 세포막의 재순환(再循環) 과정의 증거를 분석(分析)하였다. 주사전자현미경(走査電子顯微鏡) 관찰에 의하면 Turtle bladder 점막(粘膜)에는 다음 세 증류의 주요세포가 있다. 과립성세포(顆粒性細胞)는 방광점막(膀胱粘膜) 세포의 대다수를 차지하는 것으로서 총 세포수의 80%에 해당하며, 나머지 20%의 세포는 탄산탈수효소가 풍부한 A 및 B형으로 분류되는 상피세포(上皮細胞)가 특징이다. 탄산탈수효소가 풍부한 두 종류의 세포내의 관상액포(管狀液胞)나 대부분의 액포에서 horseradish peroxidase의 흡수를 조사한 결과, 세포막부분이 정단세포질(丁端細胞質) 액포에 내화(內化)되어 있었다. 마치 탄산탈수효소를 함유한 세포가 세포내(細胞內) 액포(液胞)를 소유하고 있는것 같으며 이 세포내 액포는 정단세포막으로 재순환(再循環)하는 proton 펌프를 지니는 것으로 생각된다. Turtle bladder에서 과립상세포는 두렷한 세포외분필(細胞外分泌) 기작에 의하여 다량의 mucin과 기타 단백질을 능동적으로 분비하는 constitutive pathway로서 믿어지며. 조절된 분비경로를 통해 방광상피세포(膀胱上皮細胞)가 mucin을 분비하는 가능성에 대해서는 엄밀하게 규명되어있지 않으므로 이러한 vesicular transport 상당부분이 미결상태로 남아있다.

• Nuclear Medicine and Molecular Imaging
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• 제43권6호
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• pp.519-525
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• 2009

목적: 심근의 F-18 FDG 섭취는 다양한 인자에 의해 영향을 받으며, 가역적인 허혈성 심질환이 있을 경우 심근에서 포도당 대사가 증가된다고 알려졌다. 이 연구에서는 허혈성 심질환의 과거력이 없는 종양 환자에서 시행한 F-18 FDG PET/CT에서 심근 섭취 정도 및 분포를 관찰하고, 심근 관류 SPECT와 비교하여 F-18 FDG 심근 섭취 소견으로 심근 허혈을 예측할 수 있는지를 알아보고자 하였다. 대상 및 방법: 2005년 1월부터 2009년 6월까지 F-18 FDG PET/CT를 시행한 환자 중 3개월 이내에 Tc-99m sestamibi 심근 관류 SPECT를 시행한 환자 77명을 대상으로 후향적 분석을 시행하였다. 결과: 77명의 환자 중 F-18 FDG PET/CT에서 심근에 섭취가 증가하여 있는 경우는 55명(71.4%)이었다. 이 중 40명은 균등 심근 섭취를 보였고 15명은 국소 심근 섭취를 보였다. 균등 F-18 FDG 섭취 증가를 보인 40명의 환자 중 17명(42.5%)에서 격벽에 섭취 감소가 관찰되었으나, 심근 관류 SPECT상 유의한 관류 이상은 관찰되지 않았다. 전체 심근에 균등한 섭취를 보인 23명(57.5%) 중 1명(4.3%)에서 하벽에 가역적인 관류 결손이 관찰되었고, 1명(4.3%)에서 측벽에 비가역적인 관류 결손이 관찰되었으며, 21명(91.3%)에서는 관류 결손이 관찰되지 않았다. 국소 심근 섭취를 보인 15명 중 9명(60.0%)은 기저부에 국소 섭취 증가를 보였고, 이 중 1명에서 심첨측벽에 가역적인 관류 결손이 관찰되었다. 국소적인 심근 섭취를 보인 나머지 6명(40.0%)의 환자 중에서 4명(66.7%)의 환자에서 가역적인 관류 결손이 관찰되었다. 결론: 전신 F-18 PET/CT에서 심근에 격벽 감소나 기저부 증가를 제외한 국소적인 섭취 증가가 관찰되는 경우에는 허혈성 심질환의 가능성이 있으므로 추가적인 진단 검사가 필요하다.

• 대한수의학회지
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• 제36권4호
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• pp.783-794
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• 1996

이온운반계는 생체의 각기 다른 세포의 성장을 조절하는 성장조절인자들의 효과를 매개하는데 깊은 관련이 있는 것으로 보고되고 있다. 신장 근위세뇨관에서 솔변 연 $Na^+/H^+$ 상호운반계는 사구체에서 여과된 나트륨의 재흡수와 수소이온의 분비를 조절하는 중요한 기능을 수행한다. 이 연구는 초대배양된 신장 근위세뇨관세포의 나트륨 운반을 Insulin-like Growth Factor-I(IGF-I)이 어떤 경로를 통하여 조절하는지를 알아보고자 실시하였다. 결과는 아래와 같다. 1. 초대배양된 신장 근위세뇨관세포에서 $Na^+$ uptake는 시간의존적으로 증가되었으며, 30분동안 $Na^+$ uptake를 실시한 결과 세포외 NaCl 농도의존적으로 $Na^+$ uptake를 유의성있게 감소시켰다(대조군; $40.11{\pm}1.76$, 140mM군; $17.82{\pm}0.94pmole\;Na^+/mg\;protein/min$). 2. $Na^+$ uptake는 iodoacetic acid(IAA, $1{\times}10^{-4}M$) 또는 valinomycin($5{\times}10^{-6}M$)처리시 대조군에 비해 각각 $50.51{\pm}4.4%$와 $57.65{\pm}2.27%$ 억제되었으며, ouabain($5{\times}10^{-5}M$)을 처리한 경우는 $140.23{\pm}3.37%$ 증가되었다. IGF-I($1{\times}10^{-5}M$)으로 배양한 세포를 actinomycin D($1{\times}10^{-7}M$)와 cycloheximide($4{\times}10^{-5}M$)로 처리시 $Na^+$ uptake는 대조군에 비해 각각 $90.21{\pm}2.39%$와 $89.64{\pm}3.69%$로 감소되었다. 3. IGF-I으로 배양한 세포에서 세포외 cAMP는 농도의존적($10^{-8}-10^{-4}M$)으로 $Na^+$ uptake를 유의성있게 감소시켰고, 3-isobutyl-1-methyl-xanthine(IBMX, $5{\times}10^{-5}M$)도 억제시켰다. Pertussis toxin(PTX, 50pg/ml)이나 cholera toxin(CTX, $1{\mu}g/ml$)의 처리시에도 $Na^+$ uptake는 억제되었다. 세포외 phorbol 12-myristate 13 acetate(PMA) 또한 농도의존적(1-100ng/ml)으로 $Na^+$ uptake를 감소시켰다. 그러나 staurosporine($1{\times}10^{-7}M$)은 $Na^+$ uptake에 영향을 미치지 않았으며 PMA와 stauiosporine을 동시에 처리했을 때도 $Na^+$ uptake는 억제되지 않았다. 결론적으로 초대배양된 토끼 신장 근위세뇨관세포에서 $Na^+$ uptake는 막전위와 세포내 에너지 의존적이며 IGF-I은 부분적으로 단백질 및 RNA 합성을 통해서 그리고 세포내 cAMP나 PKC 경로를 통해서 $Na^+$ uptake를 조절하는 것으로 생각된다.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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• pp.27-27
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• 2001

In exocrine acinar cells, $Ca^{2＋}$ -activated Cl$^{[-10]}$ channels in the apical membrane are essential for fluid secretion, but it is unclear whether such channels are important for Cl$^{[-10]}$ uptake at the base. Whole cell current recording, combined with local uncaging of caged $Ca^{2＋}$, was used to reveal the Cl$^{[-10]}$ channel distribution in mouse pancreatic acinar cells, where ~90％ of the current activated by $Ca^{2＋}$ in response toacetylcholine was carried by Cl$^{[-10]}$ .(omitted)

• 대한핵의학회지
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• 제26권2호
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• pp.274-279
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• 1992

Clinical role of $^{99m}Tc-MIBI$ myocardial scintigraphy in the diagnosis of coronary artery disease (CAD) is now well accepted, however, the role of it in the identification of viable myocardium in patients with chronic CAD has not yet been clarified. To determine the usefulness of rest-injected $^{99m}Tc-MIBI$ scan as a marker of myocardial viability, the regional uptake of this agent at rest was compared with that of $^{201}Tl$ on reinjection and 24 hours after reinjection images. Subject patients were 13 chronic CAD patients who showed irreversible perfusion defect(s) on standard pharmacologic (dipyridamole) stress-redistribution images. Immediately after the redistribution images were obtained, 37 MBq thallium was injected at rest, and images were reacquired at 10 minutes and 24 hours after reinjection. After then 740 MBq $^{99m}Tc-MIBI$ was injected, and 1 hour later rest MIBI myocardial imaging was performed. Five sets of imagestress, redistribution, reinjection, delayed images of thallium, and rest image of MIBI) were then analyzed qualitatively and quantitatively. Left ventricle was arbitrarily divided into 9 segments (apex, basal and apical portions of anterior, septal, inferior, and lateral walls). Seven patients and 30 regions showed a fixed perfusion defect on the stress-redistribution images. Among 30 regions, 15 showed positive uptakes and 6 showed negative uptakes on both $^{201}Tl$ reinjection/delayed images and $^{99m}Tc-MIBI$ rest images. Five regions showed only thallium uptake and were regarded as viable clinically. Of four regions which showed only $^{99m}Tc-MIBI$ uptake, two were regarded as viable, while the other two were regarded as a nonviable scar tissue clinically. In conclusion, $^{201}Tl$ reinjection technique was more reliable in the identification of viable myocardium. However, the role of $^{99m}Tc-MIBI$ in identification of viable myocardium was still remained to be clarified because 2 of 9 regions showed only $^{99m}Tc-MIBI$ uptake and were regarded as viable tissues.