• The Korean Journal of Physiology
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• 제24권2호
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• pp.345-352
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• 1990

To determine the role of sulfhydryl group in transport of organic ions across the basolateral membrane of renal proximal tubules, effect of p-chloromercuribenzoic acid (PCMB) on the transport of tetraethylammonium (TEA) and p-aminohippurate (PAH) was studied in rabbit renal cortical slices. PCMB caused irreversible inhibition of TEA and PAH uptake in a dose-dependent manner, with $I_{50}$ value (concentration for 50% inhibition) of $30\;{\mu}M$ for TEA and $75\;{\mu}M$ for PAH. Kinetic analysis of TEA and PAH uptakes showed that PCMB decreased Vmax $(62.35\;vs.\;28.32\;n\;mole/g{\cdot}min\;fur\;TEA:\;385.24\;vs.\;170.36\;n\;mole/g{\cdot}min\;for\;PAH)$ without changing Km. The inhibitory action of PCMB on TEA and PAH uptakes was independent of pH of the pretreatment medium. The inhibitory effect of PCMB on the uptake of TEA or PAH was prevented by dithiothreitol, but not by the substrate. PCMB inhibited Na-K-ATPase activity in a dose-dependent manner with $I_{50}$ value of $50\;{\mu}M$, which is similar to those for TEA and PAH uptake. These results suggest that PCMB inhibits the transport of organic cations and anions in the renal basolateral membrane by directly affecting the SH-group in the transporter molecules or secondly by altering the Na-K-ATPase activity.

• The Korean Journal of Physiology
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• 제20권2호
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• pp.225-235
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• 1986

가토 근위세뇨관에서 Percoll gradient에 의해 분리한 기저막소포(basolateral membrane vesicle)에서 PAH 이동에 미치는 여러 음이온들의 영향을 rapid filtration technique을 이용하여 관찰하였다. NA-dependent PAH 축적은 용액내 $SO_4$와 $SSO_3$에 의하여 유의하게 억제되었으나 $Cl,\;SCN,\;HPO_4,\;acetate$ 및 oxalate에 의해서는 영향을 받지 않았다. 용액내의 $SO_4$는 상경적으로 PHA 이동을 억제하였다. 소포내 음이온을 부하시킨 후 PAH 이동을 측정했을 때 $acetate,\;SO_4$ 및 PAH의 부하에 의해 PAH 이동은 유의하게 증가되었으며, 소포내 부하되는 $SO_4$농도가 증가함에 따라 PAH 축적은 증가되었다. $SO_4$에 의한 PAH의 trans-stimulation은 Na 농도 경사 존재시 더욱 증가되었으며 이들은 2 mM probenecid 및 1mM SITS에 의해 억제되었다. 이들 결과들은 신피질세뇨관 세포의 기저막에 PAH/음이온 교환에 의해 PAH가 이동되는 기전이 존재한다는 것을 가르킨다. 그러나 PAH 이동에 영향이 없는 음이온들은 PAH/음이온 교환에 기질로써 작용하지 않기 때문인지 아니면 이들 음이온들의 높은 투과성에 인해 나타난 결과인지는 더욱 추구해 보아야 확인될 것으로 생각된다.

• 대한수의학회지
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• 제35권4호
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• pp.729-733
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• 1995

This study was carried out to determine the effect of renal ischemia on renal function and excretion of amino acid in rabbit. The animal models of renal ischemia induced experimentally by clamping the renal artery for different lengths of time. These results were summarized as follows: 1. Ischemia for 30 or 60 min produced a polyuria which is accompanied by an increase in $Na^+$ excretion. Glomerular filtration rate (GFR) and p-aminohippurate plasma($C_{PAH}$) were not altered by 30 min of ischemia, indicating that transient ischemia results in a marked tubular dysfuction before a reduction in GFR or renal blood flow. 2. Reabsorption of glucose and amino acids such as alanine and lysine was markedly reduced after 30 min of ischemia, and the effect was more pronounced after 60 min of ischemia.

• 대한의생명과학회지
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• 제7권3호
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• pp.127-131
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• 2001

This study was undertaken to examine the effect of amino acids on anoxia-induced cell injury in rabbit renal cortical slices. In order to induce anoxic cell injury, slices were exposed to a 100% $N_2$ atmosphere and control slices were exposed to 100% $O^2$. Irreversible cell injury was estimated by measuring lactate dehydrogenase (LDH) release and alterations in renal cell function were examined by measuring p-aminohippurate (PAH) uptake. Anoxia caused the increase in LDH release in a time-dependent manner. Glycine and glutathione almost completely prevented anoxia-induced LDH release. Of amino acids tested, glycine and alanine exerted the protective effect against anoxia-induced cell injury. However, asparagine with amide side chain, leucine and valine with hydrocarbon side chain, and basic amino acids (lysine, histidine, and arginine) were not effective. Anoxia-induced inhibition of PAM uptake was prevented by glycine. ATP content was decreased by anoxia, which was not affected by glycine. Anoxia-induced depletion of glutathione was significantly prevented by glycine. These results suggest that neutral amino acids with simple structure exert the Protective effect against anoxia-induced cell injury the involvement of specific interaction of amino acids and cell structure.

• Journal of Acupuncture Research
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• 제19권3호
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• pp.156-167
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• 2002

The present study was carried out to determine if Scutellaria balicalensis Georgi. extract (SBGE) exerts beneficial effect against the renal failure in rabbits. Rabbits were pretreated with SBGE orally for 7 days, followed by cisplatin injection (5 mg/kg, i.p.), cisplatin injection caused an increase in serum creatinine level, which was accompanied by a reduction in GFR. The fractional excretion of Na+, K+, glucose, and phosphate increased in cisplatin-treated animals, which was prevented by SBGE pretreatment. The uptake of p-aminohippurate, an organic anion, in renal cortical slices was inhibited by the administration of cisplatin, and the effect was prevented by SBGE. cisplatin injection increased lipid peroxidation, which was prevented by SBGE pretreatment. These results indicate that lipid peroxidation plays a critical role in cisplatin-induced acute renal failure. SBGE exerts the protective effect against acute renal failure induced by cisplatin, and its effect may be attributed to an antioxidant action.

• 대한의생명과학회지
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• 제10권4호
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• pp.341-346
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• 2004

Tumor necrosis factor-α (TNF-α) or its mRNA expression are increased in acute nephrosis of various types including ischemia/reperfusion injury. This study was undertaken to determine whether pentoxifylline (PTX), an inhibitor of TNF-α production, provides a protective effect against hypoxia-induced cell injury in rabbit renal cortical slices. To induce hypoxia-induced cell injury, renal cortical slices were exposed to 100% N₂ atmosphere. Control slices were exposed to 100% O₂ atmosphere. The cell injury was estimated by measuring lactate dehydrogenase (LDH) release and p-aminohippurate (PAH) uptake. Exposure of slices to hypoxia increased the LDH release in a time-dependent manner. However, when slices were exposed to hypoxia in the presence of PTX, the LDH release was decreased. The protective effect of PTX was dose-dependent over the concentrations of 0.05∼1 mM. Hypoxia did not increase lipid peroxidation, whereas an organic hydroperoxide t-butylhydroperoxide (tBHP) resulted in a significant increase in lipid peroxidation. PTX did not affect tBHP-induced lipid peroxidation. Hypoxia decreased PAH uptake, which was significantly attenuated by PTX and glycine. tBHP-induced inhibition of PAH uptake was not altered by PTX, although it was prevented by antioxidant deferoxarnine. The PAH uptake by slices in rabbits with ischemic acute renal failure was prevented by PTX pretreatment. These results suggest that PTX may exert a protective effect against hypoxia-induced cell injury and its effect may due to inhibition of the TNF-α production, but not by its antioxidant action.

• The Korean Journal of Physiology
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• 제22권1호
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• pp.55-62
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• 1988

가토 신피질 절편에서 p-aminohippurate (PAH) 이동에 대한 카드뮴 이온(Cd)의 영향을 조사하여 다음과 같은 결과를 얻었다. 조직절편과 용액내의 PAH 농도비(S/M PAH)는 용액내에 Cd이 0.1 mM이상 존재할 때에 현저히 감소되었다. PAH influx에 대한 동력학적 분석결과 Cd에 의하여 influx의 최대이동율(즉 $V_{max}$)은 심하게 감소되지만 운반체와 기질간의 친화력(즉 $K_{m}$)에는 변화가 없었으며, 수동적 influx 역시 변화되지 않았다. 신피질조직의 산소 소모율은 1 mM Cd에 의하여 35% 가량 억제되었으며, 신피질 microsome 분획의 Na-K-ATPase 활성도는 Cd 농도가 $10^{-7}M$ 이상일 때 의의있게 억제되었다. 이상의 결과로 미루어 볼 때 신장조직이 카드뮴이온에 직접 노출될 경우 유기음이온의 능동적 이동능이 심하게 저해된다고 사료된다.

• Parasites, Hosts and Diseases
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• 제61권4호
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• pp.428-438
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• 2023

Clonorchis sinensis is commonly found in East Asian countries. Clonorchiasis is prevalent in these countries and can lead to various clinical symptoms. In this study, we used overlap extension polymerase chain reaction (PCR) and the Xenopus laevis oocyte expression system to isolate a cDNA encoding the choline transporter of C. sinensis (CsChT). We subsequently characterized recombinant CsChT. Expression of CsChT in X. laevis oocytes enabled efficient transport of radiolabeled choline, with no detectable uptake of arginine, α-ketoglutarate, p-aminohippurate, taurocholate, and estrone sulfate. Influx and efflux experiments showed that CsChT-mediated choline uptake was time- and sodium-dependent, with no exchange properties. Concentration-dependent analyses of revealed saturable kinetics consistent with the Michaelis-Menten equation, while nonlinear regression analyses revealed a Km value of 8.3 µM and a Vmax of 61.0 pmol/oocyte/h. These findings contribute to widen our understanding of CsChT transport properties and the cascade of choline metabolisms within C. sinensis.

• Archives of Pharmacal Research
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• 제29권5호
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• pp.424-429
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• 2006

In the present study, a human mammary epithelial cell (HMEC) culture model was developed to evaluate the potential involvement of carrier-mediated transport systems in drug transfer into milk. Trypsin-resistant HMECs were seeded on $Matrigel^{circledR}-coated$ filters to develop monolayers of functionally differentiated HMEC. Expression of the specific function of HMEC monolayers was dependent of the number of trypsin treatments. Among the monolayers with different numbers of treatment (treated 1 to 3 times), the monolayer treated 3 times (3-t-HMEC monolayer) showed the highest maximal transepithelial resistance and expression of $\beta-casein$ mRNA as an index of differentiation. Transport of tetraethylammonium (TEA) across the 3-t-HMEC monolayer in the basolateral-to-apical direction was significantly higher than that in the apical-to-basolateral direction (p<0.05), whereas such directionality was not observed for p-aminohippurate, suggesting the existence of organic cation transporters, but not organic anion transporters. In fact, expression of mRNAs of human organic cation transporter (OCT) 1 and 3 were detected in the 3-t-HMEC monolayer. These results indicate that the 3-t-HMEC monolayer is potentially useful for the evaluation of carrier-mediated secretion of drugs including organic cations into human milk.

• The Korean Journal of Physiology
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• 제30권2호
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• pp.279-288
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• 1996

Chronic exposure to cadmium impairs various renal tubular functions, including organic acid (anion) secretion. To investigate the mechanism of cadmium-induced alterations in the organic anion transport system, kinetics of p-aminohippurate (PAH) uptake was studied in renal cortical basolateral membrane vesicles (BLMV) isolated from cadmium-intoxicated rats (adult male Sprague-Dawley). Cadmium intoxication was induced by subcutaneous injections of $CdCl_{2}$ (2 mg Cd/kg per day) for 3 weeks. The renal plasma membrane vesicles were prepared by Percoll gradient centrifugation. The vesicular uptake of $^{14}C$-PAH was determined by rapid filtration technique using Millipore filter. Cadmium intoxication resulted in a marked attenuation of $Na^{+}$-dependent, ${\alpha}$-ketoglutarate (${\alpha}$KG)-driven PAH uptake with no changes in $Na^{+}$ and ${\alpha}$KG-independent transport component. Kinetic analysis indicated that Vmax, but not Km, of the $Na^{+}$-dependent, ${\alpha}$KG-driven component was reduced. A similar reduction of $Na^{+}$-dependent, ${\alpha}$KG-driven PAH uptake was observed in normal membrane vesicles directly exposed to inorganic cadmium in vitro, and this was accompanied by an inhibition of both $Na^{+}$-dependent ${\alpha}$KG uptake and ${\alpha}$KG-PAH exchange activity. These results indicate that during chronic exposure to cadmium, free cadmium ions liberated in the proximal tubular cytoplasm directly interact with the basolateral membrane and impair the active transport capacity for organic anions, most likely due to an inhibition of both $Na^{+}$-dicarboxylate cotransporter and dicarboxylate-organic anion antiporter activities.